TWI541137B - Photoelectric conversion element, photoelectrochemical cell, dye for photoelectric conversion element, and dye solution for photoelectric conversion element - Google Patents

Description

Photoelectric conversion element, photoelectrochemical cell, and pigment for photoelectric conversion element And a dye solution for a photoelectric conversion element

This application is based on the Japanese Patent Application No. 2010-124020 filed on May 31, 2010 with the Japan Intellectual Property Office, and the Japanese Patent Application filed on December 24, 2010 to the Japan Intellectual Property Office. Priority is claimed on Japanese Patent Application No. 2011-059911, filed on Jan. 17, 2011, to the Japanese Intellectual Property Office, the disclosure of which is hereby incorporated by reference. A part of the description of this specification.

The present invention relates to a photoelectric conversion element and a photoelectrochemical cell which have high conversion efficiency and excellent durability, and also relates to a dye for a photoelectric conversion element and a dye solution for a photoelectric conversion element.

The photoelectric conversion element can be used in various photo sensors, copying machines, solar cells, and the like. The photoelectric conversion element can be put into practical use by using various forms such as a metal, a semiconductor, an organic pigment, or a dye, or a combination of these. In particular, solar cells using non-drying solar energy sources do not require fuel, and can utilize endless clean energy, so that their practical use is greatly expected. Among them, the lanthanide solar cells have been researched and developed since the past, and have been continuously developed due to the consideration of national policies. However, silicon is an inorganic material with natural limits for both throughput and molecular modification.

Therefore, the dye-sensitized solar cell (Dye-Sensitized Solar The research of Cells was actively carried out. In particular, Graetzel et al. of the University of Technology, Lausanne, Switzerland, developed a dye-sensitized solar cell in which a pigment formed of a ruthenium complex is fixed on the surface of a porous titanium oxide film to achieve a common amorphous state.转换 conversion efficiency. Therefore, the dye-sensitized solar cell has attracted the attention of researchers all over the world.

Patent Document 1 describes a dye-sensitized photoelectric conversion element using semiconductor fine particles sensitized with a ruthenium complex dye by applying the above-described technique. However, the conventional ruthenium complex dye is capable of photoelectric conversion using visible light, but hardly absorbs infrared light having a long wavelength of more than 700 nm, and thus has low photoelectric conversion energy in an infrared region.

In a proposal, a photoelectric conversion element having a high conversion efficiency in an infrared region having a high wavelength of 700 nm or more by using a polymethine dye having a specific structure (for example, refer to Patent Document 2).

Further, the photoelectric conversion element must have high conversion efficiency in the initial stage of the wide wavelength region, and the reduction in conversion efficiency after use is less excellent in durability. However, the portion of the durability is not sufficiently described in the photoelectric conversion element described in Patent Document 2.

Therefore, a photoelectric conversion element and a photoelectrochemical cell having high conversion efficiency and excellent durability are necessary. Further, a dye for a photoelectric conversion element and a dye solution for a photoelectric conversion element are also necessary.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: US Patent No. 5,463,057

Patent Document 2: Japanese Patent No. 4217320

An object of the present invention is to provide a photoelectric conversion element and a photoelectrochemical cell which have high conversion efficiency and excellent durability. Another object of the present invention is to provide a dye for a photoelectric conversion element and a dye solution for a photoelectric conversion element.

As a result of intensive studies, the inventors of the present invention have found that a photoreceptor including a porous semiconductor fine particle layer having a polymethine dye (pigment compound) having a specific structure adsorbed on a conductive support, a charge transporting body, and The photoelectric conversion element having a laminated structure of the counter electrode and the photoelectrochemical cell using the same have high conversion efficiency in a wide wavelength region and excellent durability. The present invention has been implemented based on the above knowledge.

The object of the present invention is achieved in the following manner.

<1> A photoelectric conversion element comprising a photoreceptor layer comprising a dye represented by the general formula (1) and a semiconductor fine particle, wherein the dye is represented by a general formula (1) having an aliphatic group having 5 to 18 carbon atoms; The pigment of the compound.

In the above general formula (1), Q represents a tetravalent aromatic group. X ¹ and X ² are each independently represented by a sulfur atom, an oxygen atom or CR ¹ R ² . Here, R ¹ and R ² each independently represent a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group bonded with a carbon atom, and may be substituted. R and R' are each independently represented by an aliphatic group, an aromatic group, a heterocyclic group bonded by a carbon atom, and may be substituted. P ¹ and P ² are each independently represented as a pigment residue. W ¹ represents the relative ions necessary to neutralize the charge.

<2> The photoelectric conversion element according to <1>, wherein the aliphatic group having 5 to 18 carbon atoms is a branched alkyl group.

<3> The photoelectric conversion element according to <1> or <2>, wherein Q in the above general formula (1) is represented by a benzene ring or a naphthalene ring.

The photoelectric conversion element according to any one of the above aspects, wherein P ¹ and P ² in the above general formula (1) are each independently a general formula (2) or a general formula (3). Expressed.

In the above general formula (2) or general formula (3), V ¹ represents a hydrogen atom or a substituent. n is an integer of 0 to 4, and when n is 2 or more, V ¹ may be the same or different, and may be bonded to each other to form a ring.

Y is represented by S, NR ⁹ or CR ¹⁰ R ¹¹ . Wherein R ⁹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom. R ¹⁰ and R ¹¹ are each a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, which may be the same or different, or may be bonded to each other to form a ring.

Z represents an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, and may have a substituent.

R ³ to R ⁶ and R ⁸ each independently represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and may have a substituent.

R ⁷ is an oxygen atom or a carbon atom having two substituents, and the sum of substitution constants (σ _p ) of Hammett's law of two substituents is a positive number.

<5> The photoelectric conversion element according to <1>, wherein P ¹ and P ² in the above general formula (1) are each independently represented by the general formula (4) or the general formula (5).

In the above general formula (4) or general formula (5), V ^{1 is} represented by a hydrogen atom or a substituent. n is an integer of 0 to 4, and when n is 2 or more, V ¹ may be the same or different, and may be bonded to each other to form a ring.

Y is represented by S, NR ⁹ or CR ¹⁰ R ¹¹ . Wherein R ⁹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom. R ¹⁰ and R ¹¹ are each a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, which may be the same or different, or may be bonded to each other to form a ring.

Z represents an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, and may have a substituent.

<6> The photoelectric conversion element according to <4>, wherein the above V ¹ has an acidic group.

The photoelectric conversion element according to any one of <4>, wherein the above V ¹ is a hydrogen atom, a 5-carboxyl group, a 5-sulfonic acid group, a 5-methyl group or a 4,5-benzene group. Ring condensation.

<8> to <6>, or a photoelectric conversion element <7>, the V ¹ and wherein said Z is an acidic group or an acidic group with a group.

The photoelectric conversion element according to any one of <4>, wherein the general formula (2) is represented by a general formula (6), and the general formula (3) is a general Expressed by equation (7).

In (7), Y, Z, R 3 ~ R 8 and Y is the general formula (2) or general formula (3), Z, R ³ ~ R ⁸ the same as defined in the general formula (6) or general formula. V ^{12 is} represented as an acidic group. At least one of E ¹¹ to E ¹³ is represented as a pull electron group. p is an integer of 2 or more.

<10> The photoelectric conversion element according to <4>, wherein the general formula (2) is represented by a general formula (8), and the general formula (3) is represented by a general formula (9).

In the above general formula (8) or general formula (9), Y, Z, R 3 ~ R 8 and Y is the general formula (2) or general formula (3), Z, R ³ ~ R ⁸ the same as defined above. L is represented by the above formula A to formula D, and m is an integer of 0, 1, or 1 or more. When m is 2 or more, L may be different from each other. In the above formula A, Xa represents NRe, O, and S, and Re represents a hydrogen atom or a substituent. In the above formulas A and C, Ra to Rd are represented by an acidic group. In the above general formula (8), p represents an integer of 2 or more, and Rx represents an acidic group.

The photoelectric conversion element according to any one of <4>, wherein the Y is represented by S, NCH ₃ or C(CH ₃ ) ₂ , and Z is an aliphatic having 5 to 18 carbon atoms. base.

<12> to <4>, <6> ~ to any one of <11> photoelectric conversion elements, any of the above formula wherein R ⁷ is of formula (10) to (13) represented.

In the above formulas (10) to (13), Rf is represented by a hydrogen atom or a substituent.

<13> to <4>, <6> The photoelectric conversion element according to any one of to <12>, wherein R ⁷ is the formula of formula (14) or (15) represented.

The photoelectric conversion element according to any one of <1> to <13> wherein, in the above general formula (1), Q is represented by a benzene ring, and X ¹ and X ² are each independently represented by a sulfur atom and oxygen. The atom or C(CH ₃ ) ₂ , R and R′ are each independently represented as an aliphatic group having 5 to 18 carbon atoms.

The photoelectric conversion element according to any one of <1>, wherein the semiconductor fine particles are titanium oxide fine particles.

<16> A photoelectrochemical cell according to any one of <1> to <15>.

<17> A dye for a photoelectric conversion element, which comprises a compound represented by the general formula (1) having an aliphatic group having 5 to 18 carbon atoms.

In the above general formula (1), Q represents a tetravalent aromatic group. X ¹ and X ² are each independently represented by a sulfur atom, an oxygen atom or CR ¹ R ² . Here, R ¹ and R ² each independently represent a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group bonded with a carbon atom, and may be substituted. R and R' are each independently represented by an aliphatic group, an aromatic group, a heterocyclic group bonded by a carbon atom, and may be substituted. P ¹ and P ² are each independently represented as a pigment residue. W ¹ represents the relative ions necessary to neutralize the charge.

<18> A dye solution for a photoelectric conversion element, which comprises the dye for a photoelectric conversion element according to <17> which is contained in an organic solvent and which has been dissolved.

The present invention can provide a photoelectric conversion element and a photoelectrochemical cell which have high conversion efficiency and excellent durability. In addition, the present invention can provide a photoelectric conversion element A dye solution for a dye and a photoelectric conversion element.

The above described features and advantages of the present invention will be more apparent from the following description.

As a result of intensive research, the present inventors have found that a photoelectric conversion element having a photoreceptor layer having a specific pigment and semiconductor fine particles, and a photoelectric conversion cell using the same have high photoelectric conversion efficiency, durability, and particularly photoelectric conversion efficiency. Less reduction. The present invention has been implemented based on the above findings.

Next, a preferred example of the photoelectric conversion element of the present invention will be described with reference to the drawings. As shown in FIG. 1, the photoelectric conversion element 10 includes a conductive support 1, and a photoreceptor layer 2, a charge transporting body layer 3, and a counter electrode 4, which are arranged in this order on the conductive support 1. The conductive support 1 and the photoreceptor layer 2 are used to constitute the light receiving electrode 5 . The photoreceptor layer 2 has the semiconductor fine particles 22 and the sensitizing dye 21, and at least a part of the dye 21 is adsorbed to the semiconductor fine particles 22 (the pigment may be present in a part of the charge transporting layer when it is in an adsorption equilibrium state). . The conductive support 1 on which the photoreceptor layer 2 is formed functions as a working electrode in the photoelectric conversion element 10. The photoelectric conversion element 10 is operated by the external circuit 6, and can also be operated as the photoelectrochemical cell 100.

The light receiving electrode 5 is an electrode including the conductive support 1 and the photoreceptor layer (semiconductor film) 2, and the photoreceptor layer (semiconductor film) 2 contains the semiconductor fine particles 22 that adsorb the dye 21 coated on the conductive support. The light incident on the photoreceptor layer (semiconductor film) 2 can excite the dye, and the excitation pigment has High energy electronics. Therefore, the electrons can be transferred from the dye 21 to the conduction band of the semiconductor fine particles 22, and further diffused to reach the conductive support 1, and at this time, the molecules of the dye 21 form an oxidized body. The electrons on the electrode operate on the external circuit and return to the dye oxide to act as a photoelectrochemical cell. In this case, the light receiving electrode 5 operates as a negative electrode of the above battery.

The photoelectric conversion element of the present invention has a photoreceptor layer on a conductive support, and the photoreceptor layer has a porous semiconductor fine particle layer in which a specific dye described later is adsorbed. The photoreceptor layer may be designed as a single layer structure or a multilayer structure for the purpose. Further, the dye in the photoreceptor layer may be a mixture of a plurality of types of dyes, but at least a dye described later is used. When a photoreceptor layer containing the semiconductor fine particles to which the above-described dye is adsorbed is used as the photoelectric conversion element of the present invention, a photoelectric conversion element having high sensitivity to light in a wide wavelength region can be obtained. When the above-described photoelectric conversion element is used as a photoelectrochemical cell, a photoelectric conversion element which can obtain high conversion efficiency, has a small reduction in conversion efficiency, and is excellent in durability can be obtained.

(A) pigment (A1) a pigment of the general formula (1)

In the photoelectric conversion element of the present invention, a dye of a compound represented by the following general formula (1) is used. The above-mentioned dye can be used as a photoelectric conversion element and has an aliphatic group having 5 to 18 carbon atoms. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. Most preferred is an alkyl group, which may, for example, be pentyl, hexyl, heptyl, octyl, nonyl, decyl or eleven Undecyl), Dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, and the like. Preferred among the alkyl groups are branched alkyl groups which are, for example, 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5- Trimethylhexyl (3,5,5-trimethylhexyl), 2-cyclopentaneethyl, 2-cyclohexylethyl, and the like. By having an alkyl group having 5 to 18 carbon atoms, it is possible to suppress the decomposition of the dye by water and a nucleophile, and to suppress the decrease in durability caused by the water being close to the adsorption point and causing the pigment to be peeled off from the semiconductor fine particles. Further, since aggregation or excessive adsorption of the dyes can be suppressed, inefficient electron movement can be suppressed, and photoelectric conversion efficiency can be improved. Further, since the alkyl group is branched, the effect of improving the durability particularly in the above effects can be more remarkably obtained.

In the general formula (1), Q represents an aromatic group having at least a tetrafunctional or higher functional group. Examples of the aromatic group include aromatic hydrocarbons and aromatic heterocyclic rings. The aromatic hydrocarbon is, for example, benzene, naphthalin, anthracene, phenanthrene or the like, and the aromatic heterocyclic ring is, for example, anthraquinone, carbazole, pyridine or quinine. Quinoline, thiophene, furan, xanthene, thianthrene, etc., and may have a substituent other than the linking moiety. The aromatic group represented by Q is preferably an aromatic hydrocarbon, more preferably benzene or naphthalene. Here, the bond of X ² and N(R') toward Q is also included in the formula, and is bonded at the N(R') position X ² and at the X ² position N(R'). Bonded key.

Further, X ^1, X ² each independently represent a sulfur atom, an oxygen atom or a CR ¹ R ^2. X ¹ and X ^{2 are} preferably a sulfur atom or CR ¹ R ² , more preferably CR ¹ R ² . Here, R ¹ and R ² are each independently represented by a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom. Examples of the heterocyclic group bonded to a carbon atom include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole. , isothiazole, pyridine, pyridazine, pyrimidine, pyran, and the like. R ¹ and R ^{2 are} preferably an aliphatic group or an aromatic group. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. The alkyl group may, for example, be a linear or branched alkyl group, and is preferably an alkyl group having 5 to 18 carbon atoms (for example, pentyl, hexyl, heptyl, octyl, decyl, decyl, eleven, and ten Dibasic, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Among the alkyl groups, a branched alkyl group is preferred, which is, for example, 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentane Ethyl, 2-cyclohexylethyl and the like. By having an alkyl group having 5 to 18 carbon atoms, decomposition of the dye by water or a nucleophilic agent can be suppressed, and deterioration of durability due to peeling of the dye from the semiconductor fine particles can be suppressed by the water approaching the adsorption point. Further, since aggregation or excessive adsorption of the dyes can be suppressed, inefficient electron movement can be suppressed, and photoelectric conversion efficiency can be improved. Further, since the alkyl group is branched, the effect of improving the durability particularly in the above effects can be more remarkably obtained. The aromatic group is preferably benzene, naphthalene, anthracene or the like.

R and R' are each independently represented by an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, and they may be substituted. The heterocyclic group bonded with a carbon atom is, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, indole, pyrimidine, indole or the like. R and R' are preferably an aliphatic group or an aromatic group, and the number of carbon atoms of the aromatic group is preferably 5 to 16, more preferably 5 or 6. The unsubstituted aromatic group is preferably a phenyl group, a naphthyl group or the like. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group, more preferably an alkyl group having 5 to 18 carbon atoms (for example, a pentyl group, a hexyl group, a heptyl group, an octyl group, Sulfhydryl, fluorenyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). In the alkyl group, a branched alkyl group is preferred, which is, for example, 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentane Ethyl, 2-cyclohexylethyl and the like. By having an alkyl group having 5 to 18 carbon atoms, it is possible to suppress decomposition of a dye by water or a nucleophile, and it is possible to suppress a decrease in durability caused by water being close to the adsorption point and causing the pigment to be peeled off from the semiconductor fine particles. Further, since aggregation or excessive adsorption of the dyes can be suppressed, inefficient electron movement can be suppressed, and photoelectric conversion efficiency can be improved. Further, since the alkyl group is branched, the effect of improving the durability particularly in the above effects can be more remarkably obtained.

P ¹ and P ^{2 are} represented as pigment residues. The term "pigment residue" refers to a group of atoms necessary for a dye compound as a whole, in addition to the structures other than P ¹ and P ^{2 of the} general formula (1). P ¹ and P ² are a direct bond or a bond through a linker to constitute a dye of the general formula (1). The pigment (pigment compound) formed by P ¹ and P ² is, for example, cyanine, melocyanine, rhodacyanine, 3-nuclear anthocyanin, allopolar, half flower Polymethine pigments such as hemicyanine, styryl, oxonol, etc., containing acridine, dibenzopyran, thioxanthene, etc. Diarylmethine, triarylmethine, coumarin, indoaniline, indophenol, diazine, oxazine , thiazine, pyrrolopyrrolopyrone, indigo, perylene, quinacridone, naphthoquinone, bipyridyl, terpyridine (terpyridyl), tetrapyridyl, phenanthroline, and the like.

Preferably, it is a cyanine, anthocyanin, anthocyanin, a 3-nuclear anthocyanin, an allopolar, a semi-cyanine, a cinnamon, and the like. At this time, a substituent on the methine chain which forms a dye in the cyanine also forms a pigment of a squarylium ring and a croconium ring. Details of the above-mentioned dyes are described in "Heterocyclic Compounds-Cyanine Dyes and Related Compounds" published by F. M., Harmer, JOHN WILEY & SONS, New York, London, 1964. The general formula of cyanine, procyanidins, and safflower anthocyanins is preferably represented by (XI), (XII), (XIII) on pages 21 and 22 of U.S. Patent No. 5,340,694. Further, it is preferable that at least one of the methine chain portions of at least one of the pigment residues formed of P ¹ and P ² has a squaraine ring and a keto acid ring, and more preferably both.

In the dye having the structure of the above general formula (1), P ¹ and P ² are each independently represented by the following general formula (2) or general formula (3).

In the above general formula (2) and general formula (3), V ¹ represents a hydrogen atom or a substituent, n represents an integer of 0 to 4, and when n is 2 or more, V ¹ may be the same or different, and may be mutually bonded. Knot to form a ring. n is preferably 0 to 3, more preferably 0 to 2.

Y is represented by a sulfur atom, NR ⁹ or CR ¹⁰ R ¹¹ . Wherein R ⁹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom. The heterocyclic group bonded with a carbon atom is, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, indole, pyrimidine, indole or the like. A preferred example of R9 is an aliphatic group, and it is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. Further, it is more preferably an alkyl group having 5 to 18 carbon atoms (e.g., pentyl, hexyl, heptyl, octyl, decyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2 -ethylhexyl, etc.). The aromatic group is preferably benzene, naphthalene, anthracene or the like.

R ^10, R ¹¹ represents a hydrogen atom, an aliphatic group, an aromatic group or a carbon atom bonded to the heterocyclic group, R ¹⁰ and R ¹¹ may be the same or different and may be bonded to each other to form a ring. The heterocyclic group bonded with a carbon atom is, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, indole, pyrimidine, indole or the like. A preferred example of R ¹⁰ and R ¹¹ is an aliphatic group, and it is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. Further, it is more preferably an alkyl group having 5 to 18 carbon atoms (e.g., pentyl, hexyl, heptyl, octyl, decyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2 -ethylhexyl, etc.). The aromatic group is preferably benzene, naphthalene, anthracene or the like.

Z represents an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, and may have a substituent. A preferred example of the substituent is an acidic group, more preferably a group having a carboxyl group. R ³ to R ⁶ and R ^{8 are} represented by a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and may have a substituent. The heterocyclic group bonded with a carbon atom is, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, indole, pyrimidine, indole or the like. R ³ to R ⁶ and R ^{8 are} preferably a hydrogen atom or an aliphatic group. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. Further, it is more preferably an alkyl group having 5 to 18 carbon atoms (e.g., pentyl, hexyl, heptyl, octyl, decyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2 -ethylhexyl, etc.). R ³ to R ⁶ and R ^{8 are} more preferably a hydrogen atom. R ⁷ represents a divalent carbon atom in which the sum of substitution constants (σ _p ) of two substituents of an oxygen atom or a bond in Hammett's law is a positive number.

In general formula (1), at least one of R, R', P ¹ and P ² preferably has an acidic group. The acidic group refers to a substituent having a dissociative proton such as a carboxyl group, a phosphonyl group, a sulfonyl group, a boric acid group, or the like. Or a group having these groups, preferably a group having a carboxyl group. Further, the acidic group may also be in a form which is dissociated by releasing protons.

In the general formula (1), W ¹ represents a relative ion when a relative ion is required to neutralize the charge. In general, whether a pigment is a cation, an anion, or a net ionic charge is based on an auxochrome and a substituent in the pigment. When the dye having the structure of the general formula (1) has a dissociable substituent, it can be dissociated to have a negative charge. At this time, the charge of the entire molecule can be neutralized by W ¹ .

When W ¹ is a cation, it is, for example, an inorganic or organic ammonium ion (for example, tetraalkylammonium ion, pyridinium ion) or an alkali metal ion. Further, when W ¹ is an anion, it may be either an inorganic anion or an organic anion. For example, a halogen anion (for example, fluoride ion, chloride ion, bromide ion, iodide ion), substituted arylsulfonic acid ion (for example, p-toluenesulfonate ion) (p-toluenesulfonic acid ion), p-chlorobenzenesulfonic acid ion, aryldisulfonic acid ion (for example, 1,3-benzenedisulfonic acid ion (1,3- Benzene disulfonic acid ion, 1,5-naphthalenedisulfonic acid ion, 2,6-naphthalenedisulfonic acid ion, alkyl sulfate ion (eg, methyl sulfate) Ion), sulfate ion, thiocyanic acid ion, perchloric acid ion, tetrafluoroboric acid ion, picric acid ion, acetic acid An acetic acid ion, a trifluoromethane sulfonic acid ion or the like. Further, as the charge equalization counter ion, an ionic polymer or another pigment having a pigment and a reverse charge may be used, and a metal counter ion (for example, bisbenzene-1) may be used. 2-dithiolato nickel (III)).

In the above general formula (1), P ¹ and P ² are each independently represented by the following general formula (4) or general formula (5), and accordingly, a pigment having a high molar absorption coefficient can be obtained.

V ¹ , n, Z and Y are the same as defined in the above general formula (2) and general formula (3).

In the above general formula (4) or general formula (5), V ¹ represents a hydrogen atom or a substituent, n represents an integer of 0 to 4, and when n is 2 or more, V ¹ may be the same or different, and may be mutually Bonding to form a ring.

Y is represented by S, NR ⁹ or CR ¹⁰ R ¹¹ . Wherein R ⁹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom. R ¹⁰ and R ¹¹ are each a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, which may be the same or different, or may be bonded to each other to form a ring.

Z represents an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, and may have a substituent.

In the above general formula (4) or general formula (5), Y is preferably represented by a sulfur atom, NCH ₃ or C(CH ₃ ) ₂ , and Z is preferably represented by an aliphatic group having 5 to 18 carbon atoms. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. Further, it is more preferably an alkyl group having 5 to 18 carbon atoms (e.g., pentyl, hexyl, heptyl, octyl, decyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2 -ethylhexyl, etc.). By using Z as an aliphatic group having 5 to 18 carbon atoms, the amount of adsorption per unit area can be increased. In addition, aliphatic groups can also be substituted.

In the above general formulas (2) to (5), V ¹ preferably has an acidic group. The acidic group is a substituent having a dissociated proton. V ¹ may have an acidic group, and an acidic group may be bonded through a linking group. The acidic group is not particularly limited, and is, for example, a carboxyl group, a phosphonic acid group, a sulfo group, a sulfonatc group, a hydroxyl radical, or a hydroxamic group. , phosphoryl group, phosphinyl group, sulfino group, sulfinyl group, Phosphinyl group, phosphono group, thiol group (thiol group) with a sulfonyl group, and a salt thereof. The above salts are not particularly limited, and may be any of an organic salt and an inorganic salt. Representative examples include alkali metal ions (lithium (Li), sodium (Na), potassium (K), etc.), alkaline earth metal ions (magnesium (Mg), calcium (Ca), etc.), ammonium (ammonium), alkyl groups. Alkylammonium (for example, diethylammonium, tetrabutylammonium, etc.), pyridinium, alkylpyridinium (for example, methylpyridinium), hydrazine ( Guanidinium), a salt such as tetraalkylphosphonium. In the general formula (1), when there are a plurality of acidic groups, they may be the same or different.

The above acidic group of the present invention is preferably a carboxyl group, a phosphoric acid group or a phosphonium group, and more preferably a carboxyl group.

V ¹ preferably has a hydrogen atom, a 5-carboxyl group, a 5-sulfonic acid group, a 5-methyl or a 4,5-condensed benzene-ring. Here, the position number is annotated with N ⁺ as 1 counterclockwise rotation.

According to this, an effect of improving the molar absorption coefficient or improving the electron injection efficiency can be obtained.

Further, in the general formula (2) to the general formula (5), in addition to V ¹ , Z is preferably a group having an acidic group. Z is an acidic group which can be set to be the same as V ¹ . The acidic group has an action of adsorbing semiconductor fine particles in the dye of the present invention. The number of acidic groups in the dye is preferably one or more, more preferably one or two. Further, by setting both of V ¹ and Z as an acidic group, durability can be improved by an increase in adsorption force.

The above general formula (2) can be represented by the general formula (6), and the above general formula (3) can be represented by the general formula (7).

In the above general formula (6) or general formula (7), V ¹² represents an acidic group, and at least one of E ¹¹ to E ¹³ represents an electron withdrawing group, and p is an integer of 2 or more. Among them, the acidic group may be the same as the acidic group exemplified in the above V ¹ .

The electron withdrawing group is preferably a cyano group, a nitro group, a sulfonyl group, a sulfoxi group, an acyl group, or an alkoxycarbonyl group. The carbamoyl group is more preferably a cyano group, a nitro group or a sulfonyl group, and more preferably a cyano group.

In the above general formula (6), p is an integer of 2 or more, and p is preferably 2 to 5, more preferably 2 to 3. In the above general formula (6) and general formula (7), since V ^{12 is} represented as an acidic group, at least one of E ¹¹ to E ¹³ is represented as a pull electron group, and excited electrons can be strongly attracted to the semiconductor particle layer. In the vicinity of the adsorption point, the transport of electrons to the semiconductor particle layer can be efficiently performed, and the effect of improving the photoelectric conversion efficiency can be achieved. More preferably, in E ¹¹ to E ¹³ , E ¹¹ and E ¹² are electron-withdrawing groups.

The above general formula (2) is preferably represented by the general formula (8), and the above general formula (3) is preferably represented by the general formula (9).

In the above general formula (8) or general formula (9), Y, Z, and R ³ to R ^{8 have the} same definitions as Y, Z, and R ³ to R ⁸ of the general formula (2) or the general formula (3). L is represented by the above formulae A to D, and m is an integer of 0 or 1 or more, and when m is 2 or more, L may be different. In the above formula A, Xa represents NRe, O, and S, and Re represents a hydrogen atom or a substituent. In the above formula A and formula C, Ra to Rd represent a substituent. As a substituent in Ra~Re, the substituent represented by the following substituent is mentioned as a specific example.

The substituent is, for example, an aliphatic group, an aromatic group or a heterocyclic group bonded with a carbon atom, and it may be substituted. The heterocyclic group bonded with a carbon atom is, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, indole, pyrimidine, indole or the like. R and R' are preferably an aliphatic group or an aromatic group, and the number of carbon atoms of the aromatic group is preferably 5 to 16, more preferably 5 or 6. The unsubstituted aromatic group is preferably a phenyl group, a naphthyl group or the like. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkene group. The group is more preferably an alkyl group having 5 to 18 carbon atoms (for example, pentyl, hexyl, heptyl, octyl, decyl, decyl, eleven, decyl, octadecyl, cyclohexyl, 2 -ethylhexyl, etc.). In the alkyl group, a branched alkyl group is preferred, which is, for example, 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentane Ethyl, 2-cyclohexylethyl and the like. By having an alkyl group having 5 to 18 carbon atoms, it is possible to suppress decomposition of a dye by water or a nucleophile, and it is possible to suppress a decrease in durability caused by water being close to the adsorption point and causing the pigment to be peeled off from the semiconductor fine particles. Further, since aggregation or excessive adsorption of the dyes can be suppressed, inefficient electron movement can be suppressed, and photoelectric conversion efficiency can be improved. Further, since the alkyl group is branched, the effect of improving the durability particularly in the above effects can be more remarkably obtained.

In the above general formula (8), p represents an integer of 2 or more, and Rx represents an acidic group. Among them, examples of the acidic group include the same acidic groups as those exemplified above for V ¹ . Rx is preferably a group represented by formula E.

Since the above general formula (2) is represented by the general formula (8), the above general formula (3) is represented by the general formula (9), so that an effect of an absorption region enlargement or an increase in an absorption coefficient can be obtained, and photoelectric conversion efficiency can be produced. Improve the effect.

In the above general formula (3), general formula (5), and general formula (9), R7 is preferably represented by any one of formulas (10) to (13).

In the above formula, Rf is a hydrogen atom or a substituent. Examples of the substituent include an aliphatic group, an aromatic group, and a heterocyclic group bonded with a carbon atom, and these substituents may be substituted. Among them, the substituent is preferably an aliphatic group or an aromatic group. Thereby, the absorption on the short wavelength side can be enhanced.

In the above general formula (3), general formula (5) and general formula (9), R ^{7 is} preferably represented by formula (14) or formula (15).

Thereby, the effect of improving the electron injection efficiency can be obtained.

In the solution of the present invention represented by the formula (1), in the solution of tetrahydrofuran:ethanol = 1:1, the maximum absorption wavelength is preferably in the range of 670 nm to 1100 nm, more preferably in the range of 700 nm to 900 nm.

Preferred specific examples of the compound represented by the general formula (1) in the present invention are shown below, but the present invention is not limited thereto.

Further, the following is a preferred specific example of the dye having the structure of the general formula (6) to the general formula (9) in the present invention, but the present invention is not limited thereto.

In the above specific example, the basic architecture A is expressed as any of the following A-1 to A-12, and the basic architecture B is expressed as any of the following B-1 to B-11, and the basic architecture C is represented by any of C-1 to C-4 described below. Further, Z is represented by the following Z-1 to Z-5, and the linking group L is represented by any of the following L-1 to L-12.

In the specific examples 1 to 4, the basic structure A and the basic structure B are bonded to each other by carbon-carbon double bonds, and the basic structure B and the basic structure C are carbon atoms between each other using carbon-carbon double Key bond.

For example, in the above specific examples, it can be expressed as T-2, T-6, T-9, T-10, T-12, T-16, T-17, T-18, T-24, T as below. -30, T-37, T-40 ~ T-50 structural formula.

Moreover, the following pigments are also mentioned.

The synthesis of the dye having the above structure can be carried out by referring to Ukrainskii Khimicheskii Zhurnal, Vol. 40, No. 3, pp. 253-258, Dyes and Pigments, Vol. 21, pp. 227-234, and the literature cited therein.

(B) Conductive support

As shown in FIG. 1, the photoelectric conversion element of the present invention has a photoreceptor layer 2 in which a dye 21 is adsorbed on the porous semiconductor fine particles 22 on the conductive support 1. As described later, for example, after the dispersion of the semiconductor fine particles is applied to the conductive support, the photoreceptor can be produced by immersing in the dye solution of the present invention.

As the conductive support, a support which is electrically conductive like a metal or a glass or a polymer material having a conductive film layer on its surface can be used. The electrically conductive support is preferably substantially transparent. The fact that it is substantially transparent means that the transmittance of light is 10% or more, preferably 50% or more, and more preferably 80% or more. Further, a conductive metal oxide may be applied to the glass or the polymer material as the conductive support. The coating amount of the conductive metal oxide at this time is preferably 0.1 to 100 g per 1 m ² of the support of the glass or the polymer material. When a transparent conductive support is used, light is preferably incident from the side of the support. An example of the polymer material to be used is preferably tetraacetyl cellulose (TAC), polyethylene terephthalate (PET), or polyethylene terephthalate (Polyethylene Naphthalate). PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate (PAR), polysulfone (polysulfone) PSF), polyether sulfone (PES), polyetherimide (PEI), cyclic polyolefin, brominated phenoxy, and the like.

In the present invention, a preferred conductive support is a metal support. As the conductive metal support, a conductive metal support composed of any one of Group 4 to Group 13 can be used as the conductive support. Here, the group 4 to group 13 refers to an element in the long period periodic table.

The thickness of the conductive metal support of the present invention is preferably 10 μm or more and 2000 μm or less, more preferably 10 μm or more and 1000 μm or less, and still more preferably 50 μm or more and 500 μm or less. If the thickness of the conductive metal substrate is too thick, the flexibility is insufficient, and therefore, when it is used as a photoelectric conversion element, failure occurs. Further, if the thickness is too thin, the photoelectric conversion element may be damaged during use and thus may be poor.

The surface resistance of the conductive metal support used in the present invention is preferably a low surface resistance. Preferred range of surface resistance of 10Ω / m ² or less, more preferably 1Ω / m ² or less, more preferably 0.1Ω / m ² or less. When the value of the surface resistance is too high, it becomes difficult to be energized and the function of the photoelectric conversion element cannot be exhibited.

The conductive metal support is preferably at least one selected from the group consisting of titanium, aluminum, copper, nickel, iron, stainless steel, zinc, molybdenum, niobium, tantalum, and zirconium. These metals may also be alloys. Among them, titanium, aluminum, copper, nickel, iron, stainless steel, and zinc are preferable, and titanium, aluminum, and copper are more preferable, and titanium and aluminum are preferable. When aluminum is used, it is preferable to use an aluminum alloy stretch material, a 1000 series to a 7000 series (Light Metal Association: Aluminum Handbook, Light Metal Association (1978), 26).

Since the surface resistance of the conductive metal support is small, the internal resistance of the photoelectrochemical cell is lowered, and a high output battery can be obtained. In addition, when the conductive metal support is used, the support is not softened even if the conductive metal support to which the semiconductor fine particle dispersion described later is applied is heated and dried to be baked. . Therefore, by appropriately selecting the heating conditions, a porous semiconductor fine particle layer having a large specific surface area can be formed. According to the above, the amount of dye adsorption can be increased, and a photoelectric conversion element having high conversion efficiency at a high output can be provided.

Further, while continuously feeding the wound metal piece, the semiconductor fine particle dispersion liquid is applied onto the metal piece, and then heated to obtain a porous conductive support. Thereafter, the dye of the present invention is continuously applied to form a photosensitive layer on the conductive support. Through the above process, it is possible to inexpensively manufacture a photoelectric conversion element or a photoelectrochemical cell.

In the conductive metal support of the present invention, it is preferred to use a substrate provided with a conductive layer on the polymer material layer. The polymer material layer is not particularly limited, but a material which is melted when the semiconductor fine particle dispersion liquid is applied onto the conductor layer and is heated and does not change in shape is selected. The conductive layer is produced by laminating on the polymer material layer by a conventional method, for example, by extrusion coating or the like.

The polymer material layer that can be used is, for example, cellulose tetraacetate (TAC), polyethylene terephthalate (PET), polyethylene terephthalate (PEN), para-polystyrene (SPS). , polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate (PAR), polyfluorene (PSF), polyether oxime (PES), polyether phthalimide (PEI), cyclic polyolefin, Brominated phenoxy group and the like.

The conductive material layer is provided on the polymer material layer to be used as the conductive metal support of the present invention, and the polymer material layer functions as a protective layer of a photoelectric conversion element or a photoelectrochemical cell. When an electrically insulating material is used as the polymer material, the polymer material layer can function not only as a protective layer but also as an insulating layer. According to the above, the insulation of the photoelectric conversion element itself can be ensured. When the polymer material layer is used as an insulating layer, it is preferred to use a bulk resistivity of 10 ¹⁰ to 10 ²² Ω ‧ cm, and more preferably a bulk resistivity of 10 ¹¹ to 10 ¹⁹ Ω ‧ cm. When the above materials are used, if a conductive material is not particularly mixed, a conductive metal support having an insulating layer having a volume resistivity within the above range can be obtained. The conductive metal support is preferably substantially transparent. The fact that it is substantially transparent means that the transmittance of light of 400 nm to 1200 nm is 10% or more, preferably 50% or more, and more preferably 80% or more.

On the conductive metal support, a light management function may be applied to the surface. For example, an antireflection film in which a high refractive film and a low refractive index oxide film are laminated, or a light guide function may be provided.

It is preferable to have a function of blocking ultraviolet light on the conductive support. For example, there is a method in which a fluorescent material capable of converting ultraviolet light into visible light is present inside or on the surface of the polymer material layer. Further, as another preferred method, for example, a method using an ultraviolet absorber can be mentioned. The function described in Japanese Laid-Open Patent Publication No. Hei 11-250944 or the like can also be applied to the conductive support.

When the battery area is increased, the resistance value of the conductive film is increased, so that the collector electrode can also be disposed. The shape and material of the current collector electrode are preferably those described in Japanese Laid-Open Patent Publication No. Hei 11-266028. Further, a gas barrier film and/or an ion diffusion preventing film may be disposed between the polymer material layer and the conductive layer. The gas barrier film may be either a resin film or an inorganic film.

(C) semiconductor microparticles

As shown in FIG. 1, the photoelectric conversion element of the present invention has a photoreceptor layer 2 in which a dye 21 is adsorbed on the porous semiconductor fine particles 22 on the conductive support 1. As described later, for example, after the above-described conductive support is applied and dried, the dispersion of the semiconductor fine particles is immersed in the dye solution of the present invention to produce a photoreceptor.

The semiconductor fine particles are preferably fine metal particles of chalcogenide (for example, oxide, sulfide, selenide, or the like) or perovskites. Metal chalcogenide is preferred For titanium, tin, zinc, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium ), bismuth or antimony oxide, cadmium sulfide, cadmium selenide, and the like. The perovskite is preferably strontium titanate, calcium titanate or the like. Among them, titanium oxide, zinc oxide, tin oxide, and tungsten oxide are more preferred.

In the semiconductor, there is a p-type in which the carrier is an electron n-type and the carrier is a hole, but it is preferable to use the n-type in the element of the present invention from the viewpoint of conversion efficiency. In an n-type semiconductor, except for an intrinsic semiconductor (or intrinsic semiconductor) in which the concentration of the conduction band electrons having no impurity level and the carrier of the valence electron charged hole are equal, there are structural defects due to impurities. An n-type semiconductor having a high electron carrier concentration. The n-type inorganic semiconductor preferably used in the present invention is TiO ₂ , TiSrO ₃ , ZnO, Nb ₂ O ₃ , SnO ₂ , WO ₃ , Si, CdS, CdSe, V ₂ O ₅ , ZnS, ZnSe, SnSe, KTaO ₃ , FeS ₂ , PbS, InP, GaAs, CuInS ₂ , CuInSe _{2 ,} and the like. Among them, the most preferable n-type semiconductors are TiO ₂ , ZnO, SnO ₂ , WO ₃ and Nb ₂ O ₃ . Further, a semiconductor material obtained by recombining a plurality of these semiconductors can be preferably used.

The particle diameter of the semiconductor fine particles is preferably such that the average particle diameter of the primary particles is 2 nm or more and 50 nm or less for the purpose of maintaining a high viscosity of the semiconductor fine particle dispersion. Further, the ultrafine particles having an average particle diameter of the primary particles of 2 nm or more and 30 nm or less are more preferable. It is also possible to mix two or more kinds of fine particles having different particle diameter distributions, and in this case, the average size of the small particles is preferably 5 nm or less. this Further, for the purpose of scattering incident light to increase the light trapping rate, a large particle having a low content ratio of an average particle diameter of more than 50 nm may be added to the above ultrafine particles. In this case, the content of the large particles is preferably 50% or less, more preferably 20% or less, based on the mass of the particles having an average particle diameter of 50 nm or less. The average particle diameter of the large particles to be mixed for the above purpose is preferably 100 nm or more, and more preferably 250 nm or more.

The method for producing the semiconductor fine particles is preferably a sol-gel method described in "Science of Sol-Gel Method" by AGNE Chengfeng Press (1998). Further, a method of producing an oxide by hydrolyzing a chloride developed by Degussa Corporation at a high temperature in an oxyhydrogen salt is preferred. When the semiconductor fine particles are titanium oxide, it is preferably one of the above-mentioned sol ‧ gel method, gel ‧ sol method, and high temperature hydrolysis method in the oxyhydroxide of chloride, and more preferably The sulfuric acid method and the chlorine method described in "Technology of Titanium Dioxide and Application Technology" published in the Technical Bulletin (1997). Further, the sol-gel method is preferably a method described in C, J, Barbe et al., Journal of American Ceramic Society, Vol. 80, No. 12, pages 3157 to 3171, or S, D, Burnside, et al., Chemistry of Materials. The method described in Vol. 10, No. 9 on pages 2419 to 2425.

Further, as a method for producing the semiconductor fine particles, for example, a method for producing titanium oxide nanoparticles is preferably a method of dehydration by flame of titanium tetrachloride, a combustion method of titanium tetrachloride, and a stable chalcogenide misalignment. Hydrolysis of matter, hydrolysis of orthotropic acid, formation of semiconductor microparticles from soluble and insoluble fractions, dissolution and removal of soluble fractions Method, hydrothermal synthesis of aqueous peroxide solution, or method for producing titanium oxide having a core/shell structure by a sol-gel method

The crystal structure of titanium oxide is, for example, an anatase type, a brookite type or a rutile type, and is preferably an anatase type or a brookite type.

Further, a titanium oxide nanotube/nanowire nanometer column may be mixed in the titanium oxide fine particles.

Titanium oxide can also be doped by a non-metal element or the like, and in addition to a dopant which is an additive of titanium oxide, in order to improve necking adhesion and prevent reverse electron movement, The surface uses additives. The additive is preferably, for example, Indium Tin Oxide (ITO), tin oxide (SnO) particles, whiskers, fibrous graphite, graphite ‧ carbon nanotubes, zinc oxide neck bonding, weaving a fibrous material such as cellulose, a charge-transporting molecule such as a metal, an organosilicon, a dodecyl benzene sulfonic acid or a silane, and a potential tilting branch Dendrimer and the like.

For the purpose of removing surface defects or the like on the titanium oxide, the titanium oxide may be subjected to acid-base or redox treatment before the dye adsorption. Further, treatment such as etching, oxidation treatment, hydrogen peroxide treatment, dehydrogenation treatment, UV-ozone, oxygen plasma, or the like may be performed.

(D) Semiconductor microparticle dispersion

In the present invention, the semiconductor fine particle dispersion is applied onto the above-mentioned conductive support, and by heating appropriately, a porous half can be obtained. Conductor particle coating layer.

In addition to the above-described sol ‧ gel method, a method of directly depositing fine particles in a solvent when synthesizing a semiconductor, a method of pulverizing ultrafine particles by irradiating ultrasonic waves or the like, or A mechanical pulverization method such as stone grinding and mortar is used. As the dispersing solvent, water and/or various organic solvents can be used. And organic solvents, such as methanol, ethanol, isopropyl alcohol, citronellol, terpineol, and the like, ketones such as acetone, ethyl acetate Esters such as (ethyl acetate), dichloromethane, acetonitrile, and the like.

When dispersing, a small amount of a polymer such as polyethylene glycol, hydroxyethyl cellulose, carboxymethyl cellulose, a surfactant, an acid or a chelating agent may be used as needed. (chelating agent) and the like as a dispersing aid. However, before performing the film forming process on the conductive support, it is preferred to remove most of these dispersing aids in advance by a filtration method or a method using a separation membrane, or a telecentric separation method.

If the viscosity of the semiconductor fine particle dispersion is too high, the dispersion will aggregate and the film cannot be formed. Conversely, if the viscosity of the semiconductor fine particle dispersion is too low, the solution will flow out and the film cannot be formed. Accordingly, the viscosity of the dispersion is preferably at 25 ℃ ^{10N, S / m 2 ~ 300N} , S / m 2, more preferably at 25 ℃ ^{50N, S / m 2 ~ 200N} , S / m 2.

As a method of applying the semiconductor fine particle dispersion, a roller method, a dip method, or the like of an applied method can be used. In addition It is also possible to use an air knife method, a blade method, or the like of an adjustment method. Further, a method in which the application method and the adjustment method are used in the same portion is preferably described in the wire bar method disclosed in Japanese Patent Publication No. Sho 58-4589, the specification of U.S. Patent No. 2,681,294, and the like. A slide hopper method, an extrusion method, a curtain method, and the like. Moreover, it is preferred to apply the coating by a spin method or a spraying method using a general machine. The wet printing method is mainly three printing methods of relief printing, offset and gravure, and is preferably intaglio printing, rubber plate, screen printing. )Wait. Therefore, in the above method, a preferred film forming method can be selected depending on the liquid viscosity and the wet thickness. Since the semiconductor fine particle dispersion of the present invention has high viscosity and is viscous, it has a strong cohesive force, and thus it may be difficult to fuse with the support at the time of coating. In the above case, the surface of the semiconductor fine particle dispersion and the surface of the conductive support can be increased by the cleaning and hydrophilization of the surface by UV ozone treatment, so that the coating of the semiconductor fine particle dispersion becomes Easy to carry out.

The thickness of the semiconductor fine particle layer as a whole is preferably from 0.1 μm to 100 μm, and the thickness of the semiconductor fine particle layer is more preferably from 1 μm to 30 μm, and more preferably from 2 μm to 25 μm. The carrying amount of each 1 m ^{2 of the} semiconductor fine particles is preferably from 5 g to 400 g, more preferably from 5 g to 100 g.

In the layer to which the semiconductor fine particles have been applied, in order to enhance the contact between the electrons of the semiconductor fine particles and the adhesion to the support, Heat treatment is applied to dry the coated semiconductor fine particle dispersion. The porous semiconductor fine particle layer can be formed by the above heat treatment.

Further, in addition to the heat treatment, an energy source of light can also be used. For example, when titanium oxide is used as the semiconductor fine particles, light absorbed by the semiconductor fine particles such as ultraviolet light can be imparted to activate the surface, and only the semiconductor fine particles can be surface-activated by laser light or the like. The semiconductor fine particles are irradiated with light that can be absorbed by the fine particles, whereby impurities adsorbed on the surface of the particles can be decomposed by activation of the surface of the particles, and can be set to a preferable state for the above purpose. When the heat treatment and the ultraviolet light are combined, it is preferable to heat the semiconductor fine particles while irradiating the light absorbed by the fine particles at 100 ° C or higher and 250 ° C or lower, and more preferably at 100 ° C or higher and 150 ° C or lower. As described above, by exciting the semiconductor fine particles by light, the impurities which have been mixed in the fine particle layer are photo-decomposed and cleaned, and the physical bonding between the fine particles can be enhanced.

In addition to coating the semiconductor fine particle dispersion on the above-mentioned conductive support, and heating or irradiating light, other treatments may be performed. Preferred methods include, for example, energization, chemical treatment, and the like.

The pressure may be applied after the application, and the method of applying the pressure may, for example, be Japanese Patent Laid-Open Publication No. 2003-500857. Examples of the light irradiation include, for example, JP-A-2001-357896. Examples of the plasma, microwave, and electric current are exemplified by Japanese Patent Laid-Open Publication No. 2002-353453. For the chemical treatment, for example, JP-A-2001-357896 and the like can be cited.

In the above method of coating the semiconductor fine particles on the conductive support, in addition to the above-described method of applying the semiconductor fine particle dispersion on the conductive support, the conductive support can be coated with Japanese Patent No. 2664194. A method of obtaining a semiconductor fine particle film by hydrolyzing water in the air by a precursor of the semiconductor fine particles described above.

The above precursor is, for example, (NH ₄ ) ₂ TiF ₆ , titanium peroxide, a metal alkoxide, a metal complex, a metal organic acid salt or the like.

In addition, a method of forming a semiconductor film by heat treatment, light treatment, or the like with a slurry in which a metal organic oxide (alkoxy compound or the like) is applied, and a slurry which coexists with the inorganic precursor are used. The pH of the slurry and the characteristics of the dispersed titanium particles are a specific method. A binder may also be added in a small amount to these slurries, such as cellulose, fluoropolymer, cross-linked rubber, polybutyltitanate, carboxymethyl fiber. Prime.

A technique for forming a semiconductor fine particle or a precursor layer thereof, for example, a method of hydrophilizing by a physical method such as corona discharge, plasma, UV, or the like, by alkali or polyethylene dimer Chemical treatment such as polyethylenedioxythiophene and polystyrene sulfonate, formation of an interlayer film for bonding of polyaniline or the like, and the like.

The method of coating the semiconductor fine particles on the conductive support may be combined with the above (1) wet method (2) dry method or (3) other methods. (2) The dry method is preferably disclosed in Japanese Laid-Open Patent Publication No. 2000-231943. (3) Other methods are better listed in Japanese Patent Laid-Open No. 2002-134435 Newspaper and so on.

The dry method is, for example, vapor deposition or sputtering, an aerosol deposition method, or the like, and electrophoresis or electrolysis can also be used.

Further, a method of transferring the film to a film such as a plastic after the coating film is formed on the heat-resistant substrate may be used. A method of transferring by Ethylene Vinyl Acetate (EVA) as described in JP-A-2002-184475, or ultraviolet light as described in JP-A-2003-98977, A method in which a semiconductor layer and a conductive layer are formed on a sacrificial substrate of an aqueous salt-removed inorganic salt, and then transferred onto an organic substrate, and then the sacrificial substrate is removed.

In order to adsorb a large amount of pigment, it is preferred that the semiconductor fine particles have a large surface area. For example, in the state in which the semiconductor fine particles are coated on the support, the surface area thereof is preferably 10 times or more, more preferably 100 times or more, with respect to the projected area. However, the above upper limit is not particularly limited and is usually about 5,000 times. The structure of the semiconductor fine particles is preferably, for example, JP-A-2001-93591.

In general, although the thickness of the layer of the semiconductor fine particles is larger, the amount of the pigment that can be carried per unit area is increased, and the light absorption efficiency is increased, but the diffusion distance of the generated electrons is increased, and thus the charge is recombined. The loss will also increase. The preferred thickness of the semiconductor fine particle layer may vary depending on the use of the element, and is typically from 0.1 μm to 100 μm. Further, in the case of using as a photoelectrochemical cell, the thickness of the semiconductor fine particle layer is preferably from 1 μm to 50 μm, more preferably from 3 μm to 30 μm. In order to make the semiconductor fine particles adhere to each other after being applied to the support, it is also possible at 100 ° C. Heat at 10 ° ~ 10 hours at ~800 ° C. When glass is used as the support, the film forming temperature is preferably from 400 ° C to 600 ° C.

When a polymer material is used as the support, it is preferred to heat the film at 250 ° C or lower. The film forming method in the above case may be any one of (1) a wet method, (2) a dry method, and (3) an electrophoresis method (including an electrodeposition method), preferably (1) a wet method or (2). The dry method is more preferably (1) wet method.

Further, the coating amount per 1m ² of the support of the semiconductor fine particles is 0.5g ~ 500g, preferably 5g ~ 100g.

In order to adsorb the dye to the semiconductor fine particles, it is preferable to immerse the semiconductor electrode after the film formation in the dye solution for dye adsorption which is formed by the solution and the dye of the present invention. The solution to be used in the dye solution for dye adsorption is not particularly limited as long as it is a dye for a photoelectric conversion element of the present invention. For example, an organic solvent such as ethanol, methanol, isopropanol, toluene, tert-butanol, acetonitrile, acetone, n-butanol or the like can be used. Among them, ethanol and toluene are preferably used. Further, the organic solvent may be used singly or in combination of a plurality of them. In order to uniformly adsorb the dye to the semiconductor fine particles, the concentration of the above dye is preferably from 0.01 mmole/L to 1.0 mmole/L, more preferably from 0.1 mmole/L to 1.0 mmole/L.

The dye solution for dye adsorption formed by the solution and the dye of the present invention may be heated to 50 ° C to 100 ° C as needed. The adsorption of the dye can be carried out before or after the application of the semiconductor fine particles. Further, it is also possible to apply the semiconductor fine particles and the dye at the same time to adsorb the dye. Unadsorbed pigments can be removed by washing. In the baking of the coating film, it is preferred to carry out the adsorption of the pigment after baking, and more preferably to adsorb the surface of the coating film after baking. The pigment is quickly adsorbed before the water. Pigments having other structures may also be mixed within the scope not to impair the gist of the present invention. When mixing a dye, in order to dissolve all the pigments, it is necessary to use a dye solution for dye adsorption.

The amount of the dye used is preferably from 0.01 mmole to 100 mmole, more preferably from 0.1 mmole to 50 mmole, even more preferably from 0.1 mmole to 10 mmole, per 1 m ^{2 of the} support. In this case, the amount of the dye used in the present invention is preferably 5 mole% or more.

Further, the amount of adsorption of the pigment to the semiconductor fine particles is preferably 0.001 mmole to 1 mmole, more preferably 0.1 mmole to 0.5 mmole, per 1 g of the semiconductor fine particles.

According to the amount of the dye as described above, the sensitizing effect in the semiconductor can be sufficiently obtained. According to this, when the amount of the pigment is small, the sensitizing effect is insufficient, and when the amount of the pigment is too large, the dye which is not attached to the semiconductor is suspended, which causes the sensitization effect to be lowered.

Further, for the purpose of reducing the interaction between the dyes such as aggregation, a colorless compound may be co-adsorbed. Examples of the co-adsorbed hydrophobic compound include a steroid compound having a carboxyl group (for example, cholic acid or pivaloyl acid).

After adsorbing the pigment, an amine may also be used to treat the surface of the semiconductor fine particles. Preferred amines are, for example, 4-tert-butylpyridine, polyvinylpyridine and the like. The above amines may be used as they are in the case of a liquid, or may be dissolved in an organic solvent.

The counter electrode can function as a positive electrode of a photoelectrochemical cell. Correct The electrode is synonymous with the above-described conductive support. However, if the structure is sufficiently strong, the support is not necessarily required. However, those having a support are advantageous from the viewpoint of airtightness. The material of the counter electrode is, for example, platinum, carbon, or a conductive polymer, and is preferably platinum, carbon, or a conductive polymer.

The structure of the counter electrode is preferably a structure having a high current collecting effect, and a preferred example is Japanese Patent Laid-Open No. Hei 10-505192.

A composite electrode of titanium oxide and tin oxide (TiO ₂ /SnO ₂ ) may be used as the light-receiving electrode, and a mixed electrode of titanium oxide may be described in JP-A-2000-113913. The mixed electrode other than the titanium oxide is exemplified by those described in JP-A-2001-185243 and JP-A-2003-282164.

In order to increase the utilization of the incident light and the like, the light-receiving electrode may be of a tandem type, and an example of a preferred tandem type structure is exemplified in Japanese Laid-Open Patent Publication No. 2002-90989.

It is also possible to provide a light management function for efficiently performing light scattering and reflection inside the light-receiving electrode layer, and is preferably described in Japanese Laid-Open Patent Publication No. 2002-93476.

It is preferable to form a short circuit preventing layer between the conductive support and the porous semiconductor fine particle layer in order to prevent a reverse current which is directly contacted between the electrolytic solution and the electrode. Preferably, it is described in Japanese Laid-Open Patent Publication No. Hei 06-507999.

In order to prevent contact between the light-receiving electrode and the counter electrode, it is preferred to use a spacer or a separator. Preferably, the Japanese patent The person described in the publication No. 2001-283941.

(E) electrolyte

Representative redox pairs such as iodine and iodide (eg, lithium iodide, tetrabutylammonium iodide, tetrapropylammonium iodide, etc.), alkyl viologen (eg, Combination of methyl viologen chloride, hexyl viologen bromide, benzyl viologen tetrafluoroborate and its reducing compounds, polyhydroxy benzene ( For example, hydroquinone, naphthhydroquinone, etc., in combination with its oxides, bivalent and trivalent iron complexes (eg, red prussiate and yellow blood salt (yellow) Combination of prussiate)). Among them, a combination of iodine and iodide is preferred. The organic solvent in which the redox couple is dissolved is preferably an aprotic polar solvent (for example, acetonitrile, propylene carbonate, ethylene carbonate, dimethylformamide, Dimethyl sulfoxide, sulfolane, 1,3-dimethyl imidazolinone, 3-methyl oxazolidinone, etc. ). A polymer used in a matrix of a gel electrolyte, such as polyacrylonitrile, polyvinylidene fluoride, or the like. The molten salt is mixed with polyethylene oxide, for example, by lithium iodide and at least one other lithium salt (for example, lithium acetate, lithium perchlorate, etc.). A molten salt having fluidity at room temperature. Addition of polymer in the above case The amount is from 1% by mass to 50% by mass. Further, γ-butyrolactone may be contained in the electrolyte, whereby the diffusion efficiency of the iodide ion can be increased and the conversion efficiency can be improved.

The additive in the electrolyte may be an aminopyridine compound, a benzimidazole compound, an aminotriazole compound, and an amine in addition to the above-mentioned 4-t-butyl acridine. An aminothiazole-based compound, an imidazole-based compound, an aminotriazine-based compound, a urea derivative, an amide compound, a pyrimidine compound, and a nitrogen-free heterocyclic ring.

Further, in order to improve the efficiency, a method of controlling the moisture of the electrolytic solution may also be employed. A preferred method for controlling moisture includes a method of controlling the concentration and a method of coexisting with the dehydrating agent. In order to reduce the toxicity of iodine, a clathrate compound of iodine and cyclodextrin may be used, and conversely, a method of frequently replenishing water may be used. Further, a cyclic amidine may be used, and an oxidation preventive agent, a hydrolysis inhibitor, a decomposition inhibitor, and zinc iodide may be added.

Further, a molten salt may be used as the electrolyte, and a preferred molten salt such as an ionic liquid containing an imidazolium or a triazolium type cation, an oxazolium system, a pyridine system, an anthraquinone system, and combinations thereof . These cations may be combined with a specific anion, and an additive may be added to the above-mentioned molten salt, and a liquid crystal substituent may also be added. Further, a molten salt of a quaternary ammonium salt system can also be used.

The molten salt other than the above is, for example, a mixture of lithium iodide and at least one type of lithium salt (for example, lithium acetate, lithium perchlorate, etc.), and has fluidity at room temperature. Wait.

Alternatively, it may be gelated by adding a gelling agent to an electrolytic solution including an electrolyte and a solvent to pseudo-solidify the electrolyte. The gelling agent is, for example, an organic compound having a molecular weight of 1,000 or less, a Si-containing compound having a molecular weight of 500 to 5,000, an organic salt formed of a specific acidic compound and a basic compound, a sorbitol derivative, and a polyethylene. Pyridine.

Further, a method of limiting a matrix polymer, a crosslinked polymer compound or a monomer, a crosslinking agent, an electrolyte, and a solvent to a polymer can also be used. The matrix polymer is preferably a polymer having a nitrogen-containing heterocyclic ring in a repeating unit of a main chain or a side chain, a crosslinking agent which reacts with an electrophilic compound, a polymer having a triazine structure, and a mercapto urea. (ureide) polymer, liquid crystal compound-containing polymer, ether linkage polymer, polyfluorinated vinylene, methyl acrylate, acrylic, thermosetting resin, crosslinked polyfluorene A crystal cage compound such as oxyalkyl alcohol, polyvinyl alcohol (PVA), polyolefin diol, or dextrin, or an oxygen- or sulfur-containing polymer system or a natural polymer. In the above, a base swelling type polymer or a polymer having a compound capable of forming a cation moiety and a charge shifting substance of iodine in one polymer may be added.

As the matrix polymer, a bifunctional or higher isocyanate may be used as a component, and a type of a crosslinked polymer containing a functional group such as a hydroxyl group, an amine group or a carboxyl group may also be used. In addition, it can be used by A cross-linking method of reacting a hydrosilyl group with a cross-linking polymer of a double-bonding compound, a polysulfone acid or a polycarboxylic acid, and a metal ion compound having a divalent or higher valence.

A solvent which can be preferably used in combination with the above-described electrolyte of the pseudo solid is a specific solvent containing a specific phosphoric acid ester, an ethylene carbonate-containing mixed solvent, and has a specific dielectric constant ( Solvent for solvent constant). Further, the solid electrolyte membrane may be held or the liquid electrolyte solution may be held in the pores. The method is preferably a cloth-like solid such as a conductive polymer membrane, a fibrous solid, or a filter membrane.

Further, a solid charge transport layer such as a p-type semiconductor or a hole transport material may be used instead of the above liquid electrolyte and solidified body electrolyte. The hole-transporting material is preferably a conductive polymer such as polythiophene, polyaniline, polypyrrole or polydecane, or a spiro compound or a group of two rings having a tetrahedral structure such as C or Si as a central element. An aromatic amine derivative such as triarylamine, a triphenylene derivative, a nitrogen-containing heterocyclic derivative, or a liquid crystalline cyanide derivative.

Since the redox pair can serve as a carrier for electrons, a certain concentration is necessary, and the total concentration thereof is preferably 0.01 mole/L or more, more preferably 0.1 mole/L or more, and still more preferably 0.3 mole/L or more. . The upper limit of the above concentration is not particularly limited and is usually about 5 mole/L.

[Example]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

[Phase Modulation]

0.45 g of the following (SA-1) and 0.26 g of the following (SB-1) were mixed in a mixed solvent of 10 ml of 1-butanol and 10 ml of toluene, followed by stirring at 100 ° C for 4 hours while stirring. Then, the obtained crystals were filtered under reduced pressure, and purified by silica gel column chromatography to prepare 0.26 g of the above-mentioned dye S-14.

[Experiment 1] (Production of photoelectric conversion element)

The photoelectric conversion element shown in Fig. 1 can be fabricated in the following manner.

On the glass substrate, fluorine-doped tin oxide was formed as a transparent conductive film by sputtering, and then the transparent conductive film was divided into two portions by laser cutting. Thereafter, anatase-type titanium oxide is sintered on one of the conductive films to fabricate a light-receiving electrode. Next, a dispersion liquid containing cerium particles and a gold ore-type titanium oxide in a ratio of 40:60 (mass ratio) was applied to the light-receiving electrode, and sintering was performed to form an insulating porous body. The coating amount of the semiconductor fine particles was 20 g/m ² , followed by formation of a carbon electrode as a counter electrode.

Subsequently, the mixture was immersed in an ethanol solution of the dye described in Table 1 below for 48 hours. Then, the glass to which the sensitizing dye was dyed was immersed in a 10% ethanol solution of 4-tert-butylacridine for 30 minutes, and then washed with ethanol and allowed to dry naturally. The thickness of the obtained photoreceptor was 10 μm. The amount of the pigment is preferably a type selected from the group consisting of 0.1 mmole/m ² to 10 mmole/m ² .

As the electrolytic solution, a methoxypropionitrile solution of dimethylpropylimidazolium iodide (0.5 mole/L) and iodine (0.1 mole/L) can be used.

(Measurement of the maximum absorption wavelength of the pigment)

The maximum absorption wavelength of the dye used was measured, and the results are shown in Table 1. The measurement of the maximum absorption wavelength can be carried out by using a spectrophotometer (U-4100 (trade name), manufactured by Hitachi High-Technology Co., Ltd.), and the solution can be adjusted to 2 μM using THF:ethanol = 1:1.

(Measurement of photoelectric conversion efficiency)

By using a 500W xenon lamp (manufactured by ushio Co., Ltd.), an AM1.5G filter (manufactured by Oriel) and a sharp wave filter (Kenko L-42, trade name) are used to generate a simulated sun without ultraviolet rays. Light. The intensity of the above light was 89 mW/cm ² . The above-described light was irradiated onto the produced photoelectric conversion element, and the photoelectric conversion characteristics were measured by a current-voltage measuring device (Keithley Model 238, trade name).

The measurement results of the initial values of the conversion efficiency of the photoelectrochemical cell are shown in Table 1 below as the conversion efficiency. When the conversion efficiency is 2.5% or more, it is represented by ◎, and when it is 1% or more and less than 2.5%, it is represented by ○, 0.3% or more, less than 1% is represented by Δ, and less than 0.3% is represented by ×, and the conversion efficiency is More than 0.3% are qualified, and less than 0.3% are unqualified. Further, the initial value of the conversion efficiency was evaluated as the durability as a decrease in the conversion efficiency after 500 hours. The above results, 90% or more were evaluated as ◎, 60% or more, less than 90% The evaluation was ○, 40% or more, less than 60% was evaluated as Δ, and less than 40% was evaluated as ×, and the initial value of the relative conversion efficiency was 500% or more after the conversion efficiency was 500% or more. 60% failed.

In Experiments 1 to 10, the following A-1 and A-1 were used as comparative dyes.

As is clear from Table 1, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency was an acceptable standard, and the conversion efficiency after 500 hours passed was 60% or more of the initial value, and excellent durability was exhibited.

In the case where the comparative dye is used as described above, the initial value of the conversion efficiency is an acceptable standard, but there is a problem in durability.

[Experiment 2]

A transparent conductive film was produced by forming an ITO film on a glass substrate and then laminating an FTO film thereon. Thereafter, a transparent electrode plate is obtained by forming an oxide semiconductor porous film on the transparent conductive film. Next, a photoelectrochemical cell was fabricated using this transparent electrode plate, and conversion efficiency was measured. The above methods are as follows (1) to (5).

(1) Preparation of a raw material compound solution for ITO (indium tin oxide) film

Dissolving 5.58 g of indium(III) chloride tetrahydrate and 0.23 g of tin(II) chloride dihydrate in 100 ml of ethanol as an ITO film A raw material compound solution was used.

(2) Preparation of FTO (fluorine-doped tin oxide) film raw material compound solution

0.701 g of tin (IV) chloride pentahydrate was dissolved in 10 ml of ethanol, and then a saturated aqueous solution of 0.592 g of ammonium fluoride was added, and then the above mixture was placed in an ultrasonic cleaner for about 20 minutes until completely dissolved. FTO film raw material compound solution

(3) Production of ITO/FTO transparent conductive film

After the surface of the heat-resistant glass plate having a thickness of 2 mm was chemically washed and dried, the glass plate was placed in a reactor and heated by a heater. When the heating temperature of the heater was changed to 450 ° C, the raw material compound solution for the ITO film obtained in (1) was sprayed by a nozzle having a diameter of 0.3 mm at a pressure of 0.06 MPa at a distance of 400 mm from the glass plate for 25 minutes.

After the spraying of the raw material compound solution for the ITO film described above, after 2 minutes (in the meantime, the ethanol is continuously sprayed on the surface of the glass substrate to suppress the rise of the surface temperature of the substrate), when the heating temperature of the heater becomes 530 ° C, (2) The obtained raw material compound solution for FTO film was sprayed under the same conditions for 2 minutes and 30 seconds. According to the above, a transparent electrode plate in which an ITO film having a thickness of 530 nm and an FTO film having a thickness of 170 nm were sequentially formed on a heat-resistant glass plate was obtained.

For comparison, a transparent electrode having only an ITO film having a film thickness of 530 nm and a transparent electrode having only an FTO film having a thickness of 180 nm were separately formed on a heat-resistant glass plate having a thickness of 2 mm.

The above three kinds of transparent electrodes were heated in a heating furnace at 450 ° C for 2 hours.

(4) Production of photoelectrochemical cells

Next, a photoelectrochemical cell having the structure shown in Fig. 2 of Japanese Patent No. 4260494 was produced by using the above three kinds of transparent electrode plates. The oxide semiconductor porous film is formed by dispersing titanium oxide fine particles having an average particle diameter of about 230 nm in acetonitrile to form a paste, and then coating the coating on the transparent electrode 11 by a bar coating method. The cloth was 15 μm thick, and then dried and baked at 450 ° C for 1 hour. Next, the dye described in Table 2 was carried on the oxide semiconductor porous film.

Further, a conductive substrate in which an ITO film and an FTO film are laminated on a glass plate is used, and an electrolyte containing a non-aqueous solution of iodine/iodide is used for the electrolyte. The planar size of the photoelectrochemical cell is 25 mm x 25 mm.

(5) Evaluation of photoelectrochemical cells

The photoelectrochemical cell obtained in (4) was irradiated with sunlight (AM 1.5), and the photoelectric conversion characteristics were measured by the same method as in Experiment 1, and the conversion efficiency was determined. The results are shown in Table 2. Regarding the conversion efficiency, it is expressed as a relative value when the sample numbers 2-9 are regarded as 1. Regarding the durability, the initial value of the relative conversion efficiency is 90% or more after the conversion of 500 hours, ◎, 60% or more, less than 90%, ○, 40% or more, less than 60%, △, Less than 40% are ×, and the initial value of relative conversion efficiency is 500 hours. The conversion efficiency after the conversion is 60% or more, and less than 60% is unqualified.

It can be seen from Table 2 that when the conductive layer is only the ITO film or only the FTO film, even in the photoelectrochemical cell of the present invention, the conversion efficiency is lowered, and the conductive layer is formed on the ITO film. In the case of a film, the conversion efficiency tends to be high. The above tendency is also similar in the case of the photoelectrochemical cell of the comparative example.

Nevertheless, the conversion efficiency after 60 hours of the photoelectrochemical cell of the present invention is 60% or more, and exhibits excellent durability. The photoelectrochemical cell of the comparative example had a conversion efficiency of less than 40% after 500 hours, and was found to have a problem of durability.

[Experiment 3]

A collector electrode was placed on the FTO film to fabricate a photoelectrochemical cell, and the conversion efficiency was evaluated. The evaluation was as follows, and two types of test battery (i) and test battery (iv) were used.

(test battery (i))

After the surface of the heat-resistant glass plate of 100 mm × 100 mm × 2 mm was chemically washed and dried, the glass plate was placed in a reactor, and after heating by a heater, the FTO (fluorine-doped tin) used in the above experiment 2 was used. Oxide, fluorine-doped tin oxide) A raw material compound solution for a film was sprayed by a nozzle having a diameter of 0.3 mm at a pressure of 0.06 MPa and a distance of 400 mm from the glass plate for 25 minutes to prepare a glass substrate having an FTO film.

On the surface of the substrate described above, a groove having a depth of 5 μm was formed on the lattice circuit pattern by an etching method. Then, after patterning by photolithography, etching is performed using hydrofluoric acid. In order to form metal plating, a metal conductive layer (seed layer) is formed by sputtering, and a metal wiring layer can be formed by using an additional plating layer. The metal wiring layer was formed at a height of 3 μm from the surface of the transparent substrate to the convex lens shape. The circuit width is 60 μm. From the above, the shielding layer 5 is an FTO film having a thickness of 400 nm formed by the SPD method as the electrode substrate (i). The cross-sectional shape of the electrode substrate (i) is as shown in Fig. 2 of Japanese Patent Laid-Open No. 2004-146425.

Coating and drying an oxide having an average particle diameter of 25 nm on the electrode substrate (i) After the titanium dispersion, it was heated and sintered at 450 ° C for 1 hour. Then, it was immersed in the ethanol solution of the pigment shown in Table 3 for 40 minutes to carry the pigment. Further, it is preliminary to investigate the solubility of the dye used in the present invention in various organic solvents. As a result of the above, it was found that it was soluble in toluene. Therefore, as described in Table 3, articles which were impregnated in a toluene solution for 40 minutes were also prepared.

The platinum sputtered FTO substrate was disposed opposite to the substrate by a 50 μm thick thermoplastic resin sheet, and the resin sheet was thermally melted to fix the two plates.

However, the liquid injection port of the electrolyte which was previously opened on the platinum sputtering electrode side was filled with methoxy acetonitrile containing 0.5 M of iodide salt and 0.05 M of iodine in the main component, and was filled. Between the electrodes. Further, the peripheral portion and the electrolyte injection port were sealed with an epoxy-based encapsulating resin, and a silver paint was applied to the collector terminal portion to serve as a test cell (i). Next, similar sunlight of AM 1.5 was irradiated on the test cell (i) in the same manner as in Experiment 1 to measure the conversion efficiency, and the results are shown in Table 3.

(test battery (iv))

A glass substrate having an FTO film of 100 mm × 100 mm was prepared in the same manner as in the test battery (i). On the FTO glass substrate described above, a metal wiring layer (gold circuit) was formed by an additional plating method. The metal wiring layer (gold circuit) described above has a lattice shape on the surface of the substrate, and has a circuit width of 50 μm and a circuit thickness of 5 μm. Then, on the surface thereof, an FTO film having a thickness of 300 nm was formed as a shielding layer by the SPD method as an electrode substrate (iv). When the cross section of the electrode substrate (iv) was confirmed by SEM-EDX, it was found that there may be a sneak at the bottom of the wiring which is thought to be caused by the slab bottom of the plating resist, and in the shadow Some are not covered with FTO.

Using the electrode substrate (iv), a test battery (iv) was produced in the same manner as the test battery (i). In the same manner as in Experiment 1, a similar sunlight of AM 1.5 was irradiated on the test cell (iv) to measure the conversion efficiency. The results of the initial values of the above conversion efficiency are shown in Table 3 as conversion efficiency.

When the conversion efficiency is 2.5% or more, it is represented by ◎, and when it is 1% or more and less than 2.5%, it is represented by ○, 0.3% or more, less than 1% is represented by Δ, and less than 0.3% is represented by ×, and the conversion efficiency is More than 0.3% are qualified, and less than 0.3% are unqualified. In addition, the initial conversion value of the conversion efficiency was 90% or more, and the conversion efficiency was 90% or more, and 60% or more and less than 90% were evaluated as ○, and 40% or more and less than 60% were evaluated as Δ. Less than 40% were evaluated as ×, which is shown in Table 3 as durability. Regarding the initial value of the conversion efficiency, the conversion efficiency after 500 hours is 60% or more, and less than 60% is unqualified.

According to Table 3, the conversion efficiency of the test cell using the dye of the present invention was 1% or more and showed a high value. Further, it is understood that the conversion efficiency can be improved by appropriately selecting the solvent used in the dye solution (comparison of samples 3-1 and 3-2 with samples 3-3 and 3-4). In the case of using a comparative dye, the initial value of the conversion efficiency is as high as in the present invention, but the conversion efficiency after 500 hours has largely decreased, and the decrease in durability when the dye of the present invention is used is remarkably small. And shows excellent characteristics.

[Experiment 4]

Making peroxotitanic acid and titanium oxide microparticles and using them to make oxidation Semiconductor film. Then, an oxide semiconductor film was used to fabricate a photoelectrochemical cell, and evaluation was performed.

(Production of Photoelectrochemical Cell (A)) (1) Modulation of coating liquid (A1) for forming an oxide semiconductor film

5 g of titanium hydride was suspended in 1 L of pure water, and then 400 g of a 5 mass% (%) hydrogen peroxide solution was added thereto over 30 minutes, followed by heating to 80 ° C and dissolution to prepare a solution of peroxotitanic acid. The whole amount of the above solution was fractionated by 90 volume percent (vol%), then concentrated aqueous ammonia was added to adjust the pH to pH 9, and placed in an autoclave, and subjected to hydrothermal treatment at 250 ° C for 5 hours under a saturated vapor pressure to prepare oxidation. Titanium colloidal particles (A2). The obtained titanium oxide colloidal particles are diffracted by X-rays to form an anatase-type titanium oxide having high crystallinity.

Subsequently, titanium oxide colloidal particles (A2) obtained above was concentrated to 10 mass%, mixing the above peroxy acid solution, calculated as TiO ₂ of titanium in the above-described mixed liquid to become 30 mass% by mass TiO ₂ In the manner of adding a hydroxypropyl cellulose as a film forming aid, a coating liquid (A1) for forming a semiconductor film is prepared.

(2) Production of oxide semiconductor film (A3)

Next, on the transparent glass substrate formed by doping fluorine-doped tin oxide as an electrode layer, the above coating liquid (A1) was applied and naturally dried, and then ultraviolet rays of 6000 mJ/cm ² were irradiated with a low-pressure mercury lamp to make peroxy acid. (peroxo acid) is decomposed to harden the coating film. The coating film was heated at 300 ° C for 30 minutes to decompose and anneal the hydroxypropyl cellulose to form an oxide semiconductor film (A3) on the glass substrate.

(3) Adsorption of a pigment in an oxide semiconductor film (A3)

Next, an ethanol solution having a concentration of the dye of the present invention of 3 × 10 ^-4 mole/L was prepared as a spectral sensitizing dye. The dye solution was applied to a metal oxide semiconductor film (A3) while being rotated at 100 rpm, and dried. Then, the coating and drying processes were carried out 5 times.

(4) Modulation of electrolyte solution

In a mixed solvent of acetonitrile and ethyl carbonate in a volume ratio of 1:5, tetrapropylammonium iodide was dissolved at 0.46 mole/L to make the iodine therein a concentration of 0.07 mole/L to prepare an electrolyte solution.

(5) Production of photoelectrochemical cell (A)

The glass substrate formed of the oxide semiconductor film (A3) which adsorbs the dye produced in (2) is used as an electrode on one side, and fluorine-doped tin oxide is formed as an electrode as the other electrode. Next, on the electrode, a transparent glass substrate carrying platinum was placed oppositely, and the side surface was sealed with a resin, and the electrolyte solution of (4) was sealed between the electrodes. Then, a wire was connected between the electrodes to fabricate a photoelectrochemical cell (A).

(production of photoelectrochemical cell (B))

In addition to irradiating ultraviolet rays to decompose peroxyacid to harden the film, argon (Ar) ion irradiation (manufactured by Nisshin Electric Co., Ltd., ion implantation apparatus at 200 eV for 10 hours), and an oxide semiconductor film (A3) were used. The same is done to form an oxide semiconductor film (B3).

The adsorption of the dye is performed on the oxide semiconductor film (B3) in the same manner as the oxide semiconductor film (A3). Then, a photoelectrochemical cell (B) was produced in the same manner as in the photoelectrochemical cell (A).

(Production of Photoelectrochemical Cell (C))

18.3 g of titanium tetrachloride was diluted with pure water to obtain an aqueous solution containing 1.0% by mass in terms of TiO 2 . While stirring the above aqueous solution, 15% aqueous ammonia was added to obtain a white slurry having a pH of 9.5. The slurry was filtered and washed to obtain a filter cake of water and titanium oxide gel in an amount of 10.2% by mass in terms of TiO ₂ . Then, the above filter cake and 400 g of 5% by mass of hydrogen peroxide were mixed, followed by heating to 80 ° C and dissolved to prepare a solution of peroxotitanic acid. The whole amount of the above solution was fractionated by 90 vol%, then concentrated aqueous ammonia was added to adjust the pH to pH 9, and placed in an autoclave, and hydrothermally treated at 250 ° C for 5 hours under a saturated vapor pressure to prepare titanium oxide colloidal particles (C2). .

Next, the peroxotitanic acid solution obtained above and the titanium oxide colloidal particles (C2) are used in the same manner as the oxide semiconductor film (A3) to form an oxide semiconductor film (C3), followed by an oxide semiconductor film (A3). In the same manner, the adsorption of the dye of the present invention is carried out to obtain a spectroscopic sensitizing dye. Then, a photoelectrochemical cell (C) was produced in the same manner as in the photoelectrochemical cell (A).

(production of photoelectrochemical cell (D))

18.3 g of titanium tetrachloride was diluted with pure water to obtain an aqueous solution containing 1.0% by mass in terms of TiO 2 . While stirring the above aqueous solution, 15% by mass of aqueous ammonia was added to obtain a white slurry having a pH of 9.5. After the above slurry was filtered and washed, a slurry of 0.6% water and titanium oxide gel suspended in pure water was used as TiO ₂ , hydrochloric acid was added to pH 2, and then placed in an autoclave at 180 ° C under a saturated vapor pressure. A hydrothermal treatment was carried out for 5 hours to prepare titanium oxide colloidal particles (D2).

Then, the titanium oxide colloidal particles (D2) were concentrated to 10% by mass, and hydroxypropylcellulose was added as a film forming aid so as to be 30% by mass in terms of TiO ₂ to prepare a coating liquid for forming a semiconductor film. Next, the coating liquid was applied onto a transparent glass substrate formed by doping fluorine-containing tin oxide as an electrode layer, and dried naturally, and then ultraviolet rays of 6000 mJ/cm ² were irradiated with a low-pressure mercury lamp to cure the coating film. Subsequently, the coating film was heated at 300 ° C for 30 minutes to decompose and anneal the hydroxypropyl cellulose to form an oxide semiconductor film (D3).

Next, adsorption of the dye of the present invention is carried out in the same manner as in the oxide semiconductor film (A3) to obtain a spectral sensitizing dye. Then, a photoelectrochemical cell (D) was produced in the same manner as in the photoelectrochemical cell (A).

The photoelectrochemical cells (A) to (D) were irradiated with sunlight (AM 1.5), and the photoelectric conversion efficiency was measured by the same method as in Experiment 1 to obtain conversion efficiency. The results of the initial values of the above conversion ratios are shown in Table 4 as conversion efficiency. When the conversion efficiency is 2.5% or more, it is represented by ◎, and when it is 1% or more and less than 2.5%, it is represented by ○, 0.3% or more, less than 1% is represented by Δ, and less than 0.3% is represented by ×, and the conversion efficiency is More than 0.3% are qualified, and less than 0.3% are unqualified. In addition, the initial conversion value of the conversion efficiency was 90% or more, and the conversion efficiency was 90% or more, and 60% or more and less than 90% were evaluated as ○, and 40% or more and less than 60% were evaluated as Δ. Less than 40% were evaluated as ×, and the above values are shown in Table 4 for durability. Regarding the initial value of the conversion efficiency, the conversion efficiency after 500 hours is 60% or more, and less than 60% is unqualified.

As is clear from Table 4, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency was an acceptable standard, and the conversion efficiency after 500 hours passed was 60% or more of the initial value, and showed excellent durability.

In contrast to the above, it is known that when a comparative dye is used, the initial value of the conversion efficiency is an acceptable standard, but there is a problem in durability.

[Experiment 5]

Change the method to prepare titanium oxide, made from the obtained titanium oxide An oxide semiconductor film and a photoelectrochemical cell were fabricated and evaluated.

(1) Preparation of titanium oxide by heat treatment (titanium oxide 1 (brookite type), etc.)

Using a commercially available anatase type titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., trade name ST-01), it is heated to about 900 ° C to be converted into brookite-type titanium oxide, and further heated to about 1,200 ° C. Gold red ore type titanium oxide. Then, the titanium oxide 1 (anatase type), the comparative titanium oxide 1 (brookite type), and the comparative titanium oxide 1 (gold red ore type) were sequentially compared.

(2) Synthesis of titanium oxide by wet method (titanium oxide 2 (brookite type), etc.)

954 ml of distilled water was placed in a reaction tank equipped with a reflux condenser, and the temperature was raised to 95 °C. While maintaining a stirring speed of 200 rpm, 46 ml of an aqueous solution of titanium tetrachloride (titanium content: 16.3%, specific gravity: 1.59, purity: 99.9%) was dropped into distilled water in the reaction tank at a rate of about 5.0 ml/min. At this time, be careful not to let the temperature of the reaction solution drop. As a result of the above, the concentration of titanium tetrachloride was 0.25 mole/L (2 mass% in terms of titanium oxide). In the reaction tank, the reaction liquid was turbid immediately after the dropwise addition, and the same temperature was maintained until the end of the dropwise addition, and the mixture was further heated to about the boiling point (104 ° C), and kept in the above state for 60 minutes until the reaction was completely completed.

The sol obtained by the reaction was filtered, and then a powder was formed using a vacuum dryer at 60 °C. As a result of quantitative analysis of the powder by the X-ray diffraction method, the ratio of (the peak intensity of the brookite-type 121 surface) / (the peak intensity at the three overlapping positions) was 0.38, (the main peak intensity of the gold-red ore type) The ratio of / (peak intensity at three overlapping positions) is 0.05. The titanium oxide obtained by the above is the titanium plate The ore type is about 70.0% by mass, the gold red ore type is about 1.2% by mass, and the anatase type is about 28.8% by mass of crystallinity. Further, the above-mentioned fine particles were observed by a transmission electron microscope, and the average particle diameter of the primary particles was 0.015 μm.

(titanium oxide 3 (brookite type), etc.)

The aqueous solution of titanium trichloride (titanium content: 28%, specific gravity 1.5, purity: 99.9%) was diluted with distilled water, and converted into a solution of 0.25 mol/L in terms of titanium concentration. At this time, in order to prevent the liquid temperature from rising, ice cooling was performed and kept at 50 ° C or lower. Next, 500 ml of the above solution was placed in a reaction vessel to which a reflux condenser was attached, and while ozone gas was heated to 85 ° C, an ozone gas of 80% purity was bubbling at 1 L/min for oxidation. reaction. It was kept in the above state for 2 hours until the reaction was completely completed. The obtained sol was filtered and vacuum dried to prepare a powder. As a result of quantitative analysis of the above powder by the X-ray diffraction method, the ratio of (the peak intensity of the brookite-type 121 surface) / (the peak intensity at the three overlapping positions) was 0.85, (the main peak of the gold-red type) The ratio of the intensity) / (the peak intensity at the three overlapping positions) is zero. The titanium oxide obtained by the above is about 98% by mass of the brookite type, about 0% by mass of the gold ore type, about 0% by mass of the anatase type, and about 2% of amorphous. Further, the above-mentioned fine particles were observed by a transmission electron microscope, and the average particle diameter of the primary particles was 0.05 μm.

(production and evaluation of photoelectrochemical cells)

The titanium oxides 1 to 3 prepared by the above-described method are used as a semiconductor, and a photoelectrochemical cell using a photoelectric conversion element having the structure shown in Fig. 1 described in JP-A-2000-340269 is produced by the following method.

Coating fluorine-doped tin oxide on a glass substrate to serve as a conductive Bright electrode. A coating material was prepared using individual titanium oxide particles as a raw material on the electrode surface, and a thickness of 50 μm was applied to the electrode by a bar coating method, followed by baking at 500 ° C to form a thin layer having a film thickness of about 20 μm.

As was found in Experiment 1, it was found that the dye used in the present invention has high solubility in various organic solvents. Therefore, ethanol was used as a solvent to change the concentration of the dye solution and evaluate it. The dye used in the present invention is a 2 standard dye solution of 3 × 10 ^-4 M and 6 × 10 ^-4 M. The comparative dye had low solubility in a solvent, and since it was impossible to prepare a 6 × 10 ^-4 M solution, it was evaluated using only a dye solution of 3 × 10 ^-4 M.

An ethanol solution having a concentration of the dye as shown in Table 5 was prepared, and a thin glass substrate on which the above titanium oxide was formed was immersed therein, and kept at room temperature for 12 hours. As a result of the above, the above-mentioned dye was adsorbed on a thin layer of titanium oxide.

An iodine salt of tetrapropylammonium and an acetonitrile solution of lithium iodide were used as an electrolyte, and platinum was used as a counter electrode to prepare a photoelectric conversion element having the structure shown in Fig. 1 of Japanese Laid-Open Patent Publication No. 2000-340269. The photoelectric conversion was performed by irradiating the above-described element with light of a 160 W high-pressure mercury lamp (the filter cut-off infrared portion), and measuring the initial value of the conversion efficiency in the same manner as in Experiment 1. The above results show the conversion efficiency in Table 5.

When the conversion efficiency is 2.5% or more, it is represented by ◎, and when it is 1% or more and less than 2.5%, it is represented by ○, 0.3% or more, less than 1% is represented by Δ, and less than 0.3% is represented by ×, and the conversion efficiency is More than 0.3% are qualified, and less than 0.3% are unqualified. In addition, the initial conversion value of the conversion efficiency was 90% or more, and the evaluation was ◎, and 60% or more and less than 90% were evaluated as ○, 40% or more and less than 60% were evaluated as Δ, less than 40% were evaluated as ×, and the above values are shown in Table 5. Regarding the initial value of the conversion efficiency, the conversion efficiency after 500 hours is 60% or more, and less than 60% is unqualified.

As can be seen from Table 5, the case of using the pigment of the present invention is improved by The concentration of the dye solution is known to increase the initial value of the conversion efficiency. This is considered to be because the adsorption of the pigment of titanium oxide is also increased by increasing the concentration of the dye solution. When a comparative pigment is used, the initial value of the conversion efficiency is also an acceptable standard.

However, when durability is used, it is all unqualified with respect to the case of using a comparative pigment, and when using the pigment of this invention, it shows the outstanding characteristic.

[Experiment 6]

A coating material of dispersed semiconductor fine particles was prepared using titanium oxide having different particle diameters, and then used to fabricate a photoelectrochemical cell, and its characteristics were evaluated.

[Modulation of paint] (paint 1)

The spherical TiO ₂ particles (anatase type, average particle diameter: 25 nm, hereinafter referred to as spherical TiO ₂ particles 1) were placed in a nitric acid solution, and the titanium slurry was prepared by stirring. Next, a cellulose-based binder was added to the titanium slurry as a tackifier, and kneading was carried out to prepare a coating.

(paint 2)

The spherical TiO ₂ particles 1 and spherical TiO ₂ particles (anatase type, average particle diameter: 200 nm, hereinafter referred to as spherical TiO ₂ particles 2) were placed in a nitric acid solution, and the titanium slurry was prepared by stirring. Next, a cellulose-based binder was added to the titanium paste as a tackifier, and kneading was carried out to prepare a coating material (spherical TiO ₂ particles 1: spherical TiO ₂ particles 2 = 30:70).

(paint 3)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 100 nm, aspect ratio: 5, hereinafter referred to as rod-shaped TiO ₂ particles 1) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 1: The quality of the coating 1 = 10:90 coating.

(paint 4)

In the coating material 1, rod-shaped TiO ₂ particles 1 were mixed to prepare a coating of the mass of the rod-shaped TiO ₂ particles 1 : the mass of the coating material 1 = 30:70.

(paint 5)

In the coating material 1, rod-shaped TiO ₂ particles 1 were mixed to prepare a coating of the mass of the rod-shaped TiO ₂ particles 1 : the mass of the coating material 1 = 50:50.

(paint 6)

In the coating material 1, the plate-shaped mica particles (straight particle diameter: 100 nm, aspect ratio: 6, or hereinafter referred to as plate-like mica particles 1) are mixed to modulate the mass of the plate-like mica particles 1: the mass of the coating material 1 = 20 : 80 paint.

(paint 7)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 30 nm, aspect ratio: 6.3, hereinafter referred to as rod-shaped TiO ₂ particles 2) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 2: The quality of the coating 1 = 30:70 coating.

(paint 8)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 50 nm, aspect ratio: 6.1, hereinafter referred to as rod-shaped TiO ₂ particles 3) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 3: The quality of the coating 1 = 30:70 coating.

(paint 9)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 75 nm, aspect ratio: 5.8, hereinafter referred to as rod-shaped TiO ₂ particles 4) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 4: The quality of the coating 1 = 30:70 coating.

(paint 10)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 130 nm, aspect ratio: 5.2, hereinafter referred to as rod-shaped TiO ₂ particles 5) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 5: The quality of the coating 1 = 30:70 coating.

(paint 11)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 180 nm, aspect ratio: 5, hereinafter referred to as rod-shaped TiO ₂ particles 6) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 6: The quality of the coating 1 = 30:70 coating.

(paint 12)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 240 nm, aspect ratio: 5, hereinafter referred to as rod-shaped TiO ₂ particles 7) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 7: The quality of the coating 1 = 30:70 coating.

(paint 13)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 110 nm, aspect ratio: 4.1, hereinafter referred to as rod-shaped TiO ₂ particles 8) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 8: The quality of the coating 1 = 30:70 coating.

(paint 14)

In the coating material 1, rod-shaped TiO ₂ particles (anatase type, diameter: 105 nm, aspect ratio: 3.4, hereinafter referred to as rod-shaped TiO ₂ particles 9) were mixed to prepare the mass of the rod-shaped TiO ₂ particles 0: The quality of the coating 1 = 30:70 coating.

(Photoelectrochemical cell 1)

Photoelectricity having the same structure as that of the photoelectrode 12 described in FIG. 5 of Japanese Laid-Open Patent Publication No. 2002-289274 is produced in the order shown below. Then, a photoelectrode was used to fabricate a photoelectrochemical cell 1 having a size of 10 × 10 mm having the same structure as that of the dye-sensitized solar cell 20 except for the photoelectrode.

A transparent electrode in which a fluorine-doped SnO ₂ conductive film (film thickness: 500 nm) was formed on a glass substrate was prepared.

On the SnO ₂ conductive film, the above coating was screen printed and then dried. Thereafter, baking was carried out in the air at 450 °C. Next, using the coating material 4, screen printing and baking are repeated, and a semiconductor electrode having the same structure as that of the semiconductor electrode 2 shown in FIG. 5 of the above-mentioned patent document is formed on the SnO ₂ conductive film (area of the light receiving surface: 10 mm × 10 mm, layer thickness: 10 μm, layer thickness of semiconductor layer: 6 μm, layer thickness of light-scattering layer: 4 μm, content of rod-shaped TiO ₂ particles 1 in the light-scattering layer: 30% by mass), and then production does not contain A photoelectrode that sensitizes the pigment.

Next, in the semiconductor electrode, the dye was adsorbed as follows. First, anhydrous ethanol dehydrated with magnesium ethoxide was used as a solvent, and the individual concentration of the dye described in Table 6 was dissolved therein to 3 × 10 ^-4 mol/L to prepare a dye solution. Then, the semiconductor electrode is immersed in the above solution, whereby the total amount of the dye adsorbed in the semiconductor electrode is about 1.5 × 10 ^-7 mol/cm ² to complete the photoelectrode 10.

Then, a platinum electrode (thickness of Pt film: 100 nm) having the same shape and size as the above-described photoelectrode was used as a counter electrode, and an iodine-based redox solution containing iodine and lithium iodide was prepared as an electrolyte. Then, a spacer S (trade name: "Surlyn") manufactured by DUPONT Co., Ltd. having a shape conforming to the size of the semiconductor electrode is prepared, as disclosed in Japanese Patent Laid-Open No. 2002-289274 As shown in FIG. 3 of the publication, the photoelectrode 10 is placed opposite to the counter electrode CE by the spacer S, and the above electrolyte is filled in the inside to complete the photoelectrochemical cell 1.

(Photoelectrochemical cell 2)

In the same manner as in the photoelectrochemical cell 1, the photoelectrode 10 shown in FIG. 1 described in Japanese Laid-Open Patent Publication No. 2002-289274 is produced in the same manner as in the case of the photoelectrochemical cell 1, and then produced as in Japanese Patent Laid-Open No. 2002-289274. The photoelectrochemical cell 2 having the same configuration as the dye-sensitized solar cell 20 shown in FIG. 3 described in the publication.

The coating material 2 is used as a coating material for forming a semiconductor layer. Then, the above-mentioned coating 2 was screen printed on a SnO ₂ conductive film, followed by drying. Thereafter, baking was performed in the air at 450 ° C to form a semiconductor layer.

The coating material 3 was used as the innermost layer forming coating material of the light scattering layer, and the coating material 5 was used as the outermost layer forming coating material of the light scattering layer. Then, a light scattering layer is formed on the semiconductor layer in the same manner as in the photoelectrochemical cell 1.

Then, a semiconductor electrode having the same structure as that of the semiconductor electrode 2 shown in FIG. 1 described in JP-A-2002-289274 (the area of the light-receiving surface: 10 mm × 10 mm, layer thickness: 10 μm) is formed on the SnO ₂ conductive film. , the layer thickness of the semiconductor layer: 3 m, the thickness of the innermost layer: of 4 m, the rod-shaped TiO innermost layer ₂ contained in the content of particles 1: 10 mass%, the layer thickness of the outermost layer: 3 m, The content ratio of the rod-shaped TiO ₂ particles 1 contained in the outermost layer: 50% by mass), and then a photoelectrode containing no sensitizing dye was produced. Thereafter, similarly to the photoelectrochemical cell 1, the photoelectrode and the counter electrode CE are disposed to face each other by the spacer S, and the electrolyte is filled thereinto to complete the photoelectrochemical cell 2.

(Photoelectrochemical battery 3)

In the production of the semiconductor electrode, the coating material 1 is used as a coating material for forming a semiconductor layer, and the coating material 4 is used as a coating material for forming a light-scattering layer. In the same procedure as in the photoelectrochemical cell 1, a Japanese Patent Laid-Open 2002 is prepared. A photoelectrochemical cell 3 having the same structure as that of the photoelectrochemical cell 20 shown in FIG. 3 described in Japanese Laid-Open Patent Publication No. 2002-289274, is incorporated in the photoelectrode 10 shown in FIG.

The semiconductor electrode has an area of a light-receiving surface: 10 mm × 10 mm, a layer thickness: 10 μm, a layer thickness of the semiconductor layer: 5 μm, a layer thickness of the light-scattering layer: 5 μm, and a rod-shaped TiO ₂ particle 1 contained in the light-scattering layer. Content ratio: 30% by mass.

(Photoelectrochemical battery 4)

In the production of the semiconductor electrode, the coating material 2 is used as a coating material for forming a semiconductor layer, and the coating material 6 is used as a coating material for forming a light-scattering layer. The photoelectrode 10 and the photoelectrochemical cell 4 having the same structure as the photoelectrochemical cell 20 shown in Fig. 3 described in Japanese Patent Laid-Open Publication No. 2002-289274. The semiconductor electrode has an area of a light-receiving surface: 10 mm × 10 mm, a layer thickness: 10 μm, a layer thickness of the semiconductor layer: 6.5 μm, a layer thickness of the light-scattering layer: 3.5 μm, and plate-shaped mica particles contained in the light-scattering layer. Content ratio of 1 : 20% by mass.

(Photoelectrochemical cell 5)

In the production of the semiconductor electrode, the photoelectrochemical cell 5 was produced in the same manner as the photoelectrochemical cell 1 except that the coating material 2 was used as a coating material for forming a semiconductor layer, and the coating material 8 was used as a coating material for forming a light scattering layer. The content ratio of the rod-shaped TiO ₂ particles 3 contained in the light-scattering layer of the semiconductor electrode was 30% by mass.

(Photoelectrochemical Battery 6)

In the production of the semiconductor electrode, the photoelectrochemical cell 6 was produced in the same manner as the photoelectrochemical cell 1 except that the coating material 2 was used as a coating material for forming a semiconductor layer, and the coating material 9 was used as a coating material for forming a light scattering layer. The content ratio of the rod-shaped TiO ₂ particles 4 contained in the light-scattering layer of the semiconductor electrode was 30% by mass.

(Photoelectrochemical battery 7)

In the production of the semiconductor electrode, the photoelectrochemical cell 7 was produced in the same manner as the photoelectrochemical cell 1 except that the coating material 2 was used as a coating material for forming a semiconductor layer, and the coating material 10 was used as a coating material for forming a light scattering layer. The content ratio of the rod-shaped TiO ₂ particles 5 contained in the light-scattering layer of the semiconductor electrode was 30% by mass.

(Photoelectrochemical Battery 8)

In the production of the semiconductor electrode, the photoelectrochemical cell 8 was produced in the same manner as the photoelectrochemical cell 1 except that the coating material 2 was used as a coating material for forming a semiconductor layer, and the coating material 11 was used as a coating material for forming a light scattering layer. The content ratio of the rod-shaped TiO ₂ particles 6 contained in the light-scattering layer of the semiconductor electrode was 30% by mass.

(Photoelectrochemical cell 9)

In the production of the semiconductor electrode, the photoelectrochemical cell 9 was produced in the same manner as the photoelectrochemical cell 1 except that the coating material 2 was used as a coating material for forming a semiconductor layer, and the coating material 13 was used as a coating material for forming a light scattering layer. The content ratio of the rod-shaped TiO ₂ particles 8 contained in the light-scattering layer of the semiconductor electrode was 30% by mass.

(Photoelectrochemical battery 10)

In the production of the semiconductor electrode, the photoelectrochemical cell 10 was produced in the same manner as the photoelectrochemical cell 1 except that the coating material 2 was used as a coating material for forming a semiconductor layer, and the coating material 14 was used as a coating material for forming a light scattering layer. The content ratio of the rod-shaped TiO ₂ particles 9 contained in the light-scattering layer of the semiconductor electrode was 30% by mass.

(Photoelectrochemical cell 11)

In the production of the semiconductor electrode, photoelectrochemistry was produced in the same order as in the photoelectrochemical cell 1 except that the semiconductor electrode formed of only the semiconductor layer (the area of the light-receiving surface: 10 mm × 10 mm, layer thickness: 10 μm) was produced using only the coating material 2. Battery 11.

(Photoelectrochemical cell 12)

In the production of the semiconductor electrode, the photoelectrochemical cell 12 was produced in the same manner as the photoelectrochemical cell 1 except that the coating material 2 was used as a coating material for forming a semiconductor layer, and the coating material 7 was used as a coating material for forming a light scattering layer. The content ratio of the rod-shaped TiO ₂ particles 2 contained in the light-scattering layer of the semiconductor electrode was 30% by mass.

[Test and evaluation of characteristics]

Regarding the photoelectrochemical cells 1 to 12, a solar simulator (manufactured by WACOM, WXS-85H (trade name)) was used, and the irradiation was similar to 1000 W/m ² from a xenon lamp passing through an AM 1.5 filter. sunshine. The current-voltage characteristics were measured using an IV test to obtain an initial value of the conversion efficiency. The above results are shown in Table 6.

When the conversion efficiency is 2.5% or more, it is represented by ◎, and when it is 1% or more and less than 2.5%, it is represented by ○, 0.3% or more, less than 1% is represented by Δ, and less than 0.3% is represented by ×, and the conversion efficiency is More than 0.3% are qualified, and less than 0.3% are unqualified. In addition, the initial conversion value of the conversion efficiency was 90% or more, and the conversion efficiency was 90% or more, and 60% or more and less than 90% were evaluated as ○, and 40% or more and less than 60% were evaluated as Δ. Less than 40% were evaluated as ×, and the above results are shown in Table 6. Regarding the initial value of the conversion efficiency, the conversion efficiency after 500 hours is 60% or more, and less than 60% is unqualified.

As is clear from Table 6, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency was 1% or more, and the conversion efficiency after 500 hours passed. It is 60% or more of the initial value and shows excellent durability.

In contrast to the above, when the comparative dye is used, the initial value of the conversion efficiency is an acceptable standard, but there is a problem in durability.

[Experiment 7]

A slurry of metal alkoxide is added to the metal oxide fine particles on the conductive substrate, and then subjected to UV ozone irradiation, UV irradiation or drying to prepare an electrode. Next, a photoelectrochemical cell was fabricated, and the conversion efficiency was measured.

(metal oxide microparticles)

Titanium oxide was used as the metal oxide fine particles, and titanium oxide was a P25 powder (manufactured by Deguss Co., Ltd., trade name) having a mass ratio of 30% gold red ore and 70% anatase type and an average particle diameter of 25 nm.

(Pretreatment of metal oxide microparticle powder)

The metal oxide fine particles are preheated to remove organic matter and moisture on the surface. In the case of titanium oxide fine particles, it was heated in an oven at 450 ° C for 30 minutes in the air.

(Measurement of the amount of water contained in the metal oxide fine particles)

The amount of water contained in titanium oxide and P25 powder (manufactured by Deguss Co., Ltd., trade name) stored in an environment having a temperature of 26 ° C and a humidity of 72% can be reduced by weight during thermal weight measurement and removed when heated at 300 ° C. The Karl Fischer titration of the moisture is used for quantification.

When the amount of water removed by heating the titanium oxide or the P25 powder (manufactured by Deguss Co., Ltd., trade name) at 300 ° C is quantified by Karl Fischer titration, 0.1033 g of the titanium oxide fine powder contains 0.253. Mg of water. That is, the titanium oxide fine powder contains about 2.5% by mass of water. After heat treatment and cooling for 30 minutes, it was stored in a desiccator for use.

(Modulation of metal alkoxide coatings)

The metal alkoxide which combines the action of the metal oxide fine particles respectively uses titanium tetraoxide (IV) (titanium (IV) tetraisopropoxide, TTIP) as a titanium raw material, zirconium (IV) tetra n -propoxide) as a zirconium raw material, niobium (V) pentaethoxide as a raw material for bismuth (all manufactured by Aldrich Co., Ltd.).

The molar concentration ratio of the metal oxide fine particles to the metal alkoxide is based on the metal oxide fine particles in such a manner that the amorphous layer produced by the hydrolysis of the metal alkoxide is not excessively thick and the bonding of the particles is sufficiently performed. Make appropriate adjustments to the path. Further, the metal alkoxide was used as a 0.1 M ethanol solution. In the case of mixed oxide titanium fine particles and titanium tetraisopropoxide (IV) (TTIP), 3.55 g of a 0.1 M TTIP solution was mixed with respect to 1 g of the titanium oxide fine particles. At this time, the concentration of the titanium oxide in the obtained coating material was about 22% by mass, and the viscosity was appropriately applied to the coating. Further, the mass ratio of titanium oxide to TTIP and ethanol at this time was 1:0.127:3.42, and the molar ratio was 1:0.036:5.92.

Similarly, the mixed coating of the titanium oxide fine particles and the alkoxide other than TTIP was also prepared so that the fine particle concentration was 22% by mass, and the coating using zinc oxide and tin oxide was 16% by mass. In the case of zinc oxide and tin oxide, it was mixed at a ratio of 5.25 g with respect to 1 g of the metal alkoxide solution of the metal oxide fine particles.

Next, the metal oxide microparticles and the metal alkoxide solution are placed In a closed vessel, a magnetic stirrer was used for 2 hours to obtain a uniform coating. As a method of applying the coating material on the conductive substrate, a doctor blade method, a screen printing method, a spray coating method, or the like can be used, and an appropriate coating viscosity is appropriately selected according to the coating method. Here, it is a simple glass rod coating method (similar to the doctor blade forming method). In this case, the concentration of the metal oxide fine particles to which the appropriate coating viscosity is applied is approximately in the range of 5 mass% to 30 mass%.

The thickness of the amorphous metal oxide formed by decomposing the metal alkoxide is in the range of about 0.1 to 0.6 nm in the present invention, and it can be used as a suitable thickness.

(Coating and air drying treatment of the coating on the conductive substrate)

a polyethylene terephthalate (PET) film substrate (20 Ω/cm ² ) equipped with an indium tin oxide (ITO) conductive film, or a glass substrate provided with a fluorine-doped tin oxide (FTO) conductive film ( On 10 Ω/cm ² ), two adhesive tapes were adhered in parallel at regular intervals to form a spacer, and then the coating prepared according to the above method was uniformly coated using a glass rod.

The conditions for the presence or absence of the UV ozone treatment, the UV irradiation treatment, or the drying treatment are changed after the application of the coating material and before the adsorption of the dye to prepare a porous membrane.

(drying treatment)

The film applied to the conductive substrate was air-dried in air at room temperature for about two minutes. In this process, the metal alkoxide in the coating is hydrolyzed by moisture in the atmosphere, and amorphous titanium oxide, zirconium oxide, and the like are formed from the Ti alkoxide, the Zr alkoxide, and the Nb alkoxy compound, respectively. Yttrium oxide.

(UV ozone treatment)

The UV ozone treatment was performed using an NL-UV253 UV ozone cleaning device manufactured by Laser Electronics, Japan. The UV light source was provided with three 4.5 W mercury lamps having 185 nm and 254 nm glow lines, and the sample was horizontally disposed at a distance of about 6.5 cm from the light source. Then, an oxygen gas flow is introduced in the chamber to generate ozone. In this example, UV ozone treatment was performed for 2 hours. However, the reduction in conductivity of the ITO film and the FTO film treated with the above UV ozone was not observed at all.

(UV treatment)

The treatment was carried out for 2 hours in the same manner as in the above-described UV ozone treatment except that the treatment was carried out by substituting nitrogen gas in the chamber. The decrease in conductivity of the UV-treated ITO film and the FTO film described above was not observed at all.

(pigment adsorption)

The pigment used was a 0.5 mM ethanol solution in which the dyes described in Table 7 were used. In this experiment, the porous film produced by the above process was dried in an oven at 100 ° C for 1 hour, immersed in a solution of the sensitizing dye, and then left at room temperature for 50 minutes to adsorb the pigment on the surface of the titanium oxide. . Thereafter, the sample after the dye adsorption was washed with ethanol and air-dried.

(Photoelectrochemical cell fabrication and battery characteristics evaluation)

A conductive substrate on which a porous film after dye adsorption is formed is used as a photoelectrode, and is disposed in an opposite direction to an ITO/PET film or an FTO/glass pair having platinum fine particles modified by sputtering to test a photoelectrochemical cell. . The effective area of the above photoelectrode is about 0.2 cm ² . The electrolyte solution was 3-methoxypropionitrile containing 0.5 M LiI, 0.05 M I ₂ and 0.5 M tributyl acridine, and was introduced into the gap between the electrodes by capillary action. .

The battery performance was evaluated based on the current action spectrum measurement under irradiation with a certain photon number (10 ¹⁶ cm ² ) and the IV measurement under irradiation with AM 1.5 (100 mW/cm ² ). The above measurement was performed using a CEP-2000 type spectrophotometric measuring apparatus manufactured by Spectrometer Co., Ltd., and the conversion efficiency obtained is shown in Table 7.

When the conversion efficiency is 2.0% or more, it is represented by ◎, 0.8% or more, less than 2.0% is represented by ○, 0.3% or more, less than 0.8% is represented by Δ, and less than 0.3% is represented by ×, and the conversion efficiency is More than 0.3% are qualified, and less than 0.3% are unqualified. In addition, the initial conversion value of the conversion efficiency was 90% or more, and the conversion efficiency was 90% or more, and 60% or more and less than 90% were evaluated as ○, and 40% or more and less than 60% were evaluated as Δ. Less than 40% were evaluated as ×, and the above values are shown in Table 7 as durability. Regarding the initial value of the conversion efficiency, the conversion efficiency after 500 hours is 60% or more, and less than 60% is unqualified.

In Table 7, the fields of "UV ozone", "UV", and "dry" are respectively indicated as whether or not UV ozone treatment, UV irradiation treatment, and drying treatment are performed after the formation of the porous film and before the adsorption of the sensitizing dye. The processed person is "○" and the unprocessed person is "x".

The column of "pretreatment of TiO ₂ " in Table 7 indicates the presence or absence of pretreatment of titanium oxide fine particles (heat treatment in an oven at 450 ° C for 30 minutes). Samples 6, 14, and 22 are shown as samples using a coating having a high TTIP concentration (titanium oxide: TTIP molar ratio of 1:0.356), and other samples (samples 1 to 5, 7 to 13, 23, 24) are all samples. To use a coating of titanium oxide: TTIP = 1:0.0356.

As is clear from Table 7, the photoelectrochemical cell using the dye of the present invention has a UV ozone treatment, a UV irradiation treatment, and a drying treatment after the formation of the porous membrane and before the adsorption of the sensitizing dye, compared to when the pigment is used alone. In the case, the conversion efficiency of the photoelectrochemical cell is generally high, and the conversion efficiency of an acceptable standard can be obtained. Further, the conversion efficiency after 500 hours passed was 60% or more of the initial value, and showed excellent durability.

In contrast to the above, when the comparative dye is used, the initial value of the conversion efficiency is an acceptable standard, but there is a problem in durability.

[Experiment 8]

Using acetonitrile as a solvent, lithium iodide 0.1 mol/L, iodine 0.05 mol/L, and dimethylpropylimidazolium iodide 0.62 mol/L were dissolved to prepare an electrolyte solution. Here, the polybenzimidazole-based compound of No. 1 to No. 8 shown below was separately added and dissolved so as to have a concentration of 0.5 mol/L.

A polybenzimidazole-based compound electrolyte of No. 1 to No. 8 was dropped on a porous titanium oxide semiconductor thin film (thickness: 15 μm) of the dye described in Table 8 on the conductive glass. Then, a frame type spacer (thickness: 25 μm) made of a polyethylene film was placed thereon, followed by covering the platinum counter electrode to fabricate a photoelectric conversion element.

On the obtained photoelectric conversion element, light having a light source intensity of 100 mW/cm ^{2 was} irradiated with a xenon lamp, and the obtained open voltage and photoelectric conversion efficiency are shown in Table 8.

(evaluation of results)

(i) When the open voltage is 7.0 V or more, it is indicated by ◎, and when it is 6.5 V or more and less than 7.0 V, it is represented by ○, and 6.0 V or more and less than 6.5 V are represented by Δ, and those less than 6.0 V are represented by ×, and Those who are above 6.5V are qualified.

(ii) When the conversion efficiency is 2.0% or more, it is represented by ◎, and 0.8% or more and less than 2.0% are represented by ○, and 0.3% or more and less than 0.8% are represented by Δ. Less than 0.3% is indicated by ×, and conversion efficiency is 0.3% or more, and less than 0.3% is unqualified. In addition, the initial conversion value of the conversion efficiency was 90% or more, and the conversion efficiency was 90% or more, and 60% or more and less than 90% were evaluated as ○, and 40% or more and less than 60% were evaluated as Δ. Less than 40% were evaluated as ×, and the above values are shown in Table 8 as durability. Regarding the initial value of the conversion efficiency, the conversion efficiency after 500 hours is 60% or more, and less than 60% is unqualified.

Further, in Table 8, the results of using the photoelectric conversion element of the electrolytic solution in which the polybenzimidazole-based compound was not added were also shown.

As can be seen from Table 8, the photoelectrochemical cell using the dye of the present invention has an initial value of the open voltage and the conversion efficiency, and the conversion efficiency after 500 hours is 60% or more of the initial value, and indicates Excellent durability.

In contrast to the above, when the comparative dye is used, the initial values of the open voltage and the conversion efficiency are acceptable standards, but there is a problem in durability.

[Experiment 9] (Photoelectrochemical cell 1)

A photoelectrode having the same structure as that of the photoelectrode 10 shown in FIG. 1 of Japanese Laid-Open Patent Publication No. 2004-152613 is produced in the order shown below, and then, in addition to the use of the photoelectrode, a Japanese Patent Publication No. 2004 is prepared. A photoelectrochemical cell having the same configuration as that of the dye-sensitized solar cell 20 shown in Fig. 1 of the Japanese Patent Publication No. 152613 (the area of the light-receiving surface F2 of the semiconductor electrode 2: 1 cm ² ). In the respective layers of the semiconductor electrode 2 having the two-layer structure, a layer disposed on the side close to the transparent electrode 1 is referred to as a "first layer", and a layer disposed on a side close to the porous layer PS is referred to as a "second layer". Floor".

First, P25 powder (manufactured by Deguss Co., Ltd., trade name) having an average particle diameter of 25 nm, titanium oxide particles having a different particle diameter, P200 powder (average particle diameter: 200 nm, manufactured by Deguss, trade name), and P25 and P200 were used. A total content of 15% and a mass ratio of P25 to P200 of P25:P200=30:70, in which acetylacetone, ion-exchanged water, and a surfactant (manufactured by Tokyo Chemical Industry Co., Ltd., trade name) are added. "Triton-X"), and kneading was carried out to prepare a slurry for forming a second layer (hereinafter referred to as "slurry 1").

Then, the slurry for forming the first layer is prepared by the same modulation sequence as that of the above-described slurry 1 (P1 content: 15%, hereinafter referred to as "slurry 2"), except that P200 is used instead of P25. ).

In one aspect, on a glass substrate (transparent conductive glass), prepared formed conductive fluorine-doped SnO ₂ film (film thickness: 700nm) transparent electrode. Next, the above slurry 2 was applied onto a SnO ₂ conductive film by a bar coating method, and then dried. Thereafter, baking was performed in air at 450 ° C for 30 minutes. As described above, the first layer of the semiconductor electrode 2 is formed on the transparent electrode.

Then, using the slurry 1, the second layer was formed on the first layer by repeating the same coating and baking as described above. As described above, the semiconductor electrode 2 is formed on the SnO ₂ conductive film (the area of the light-receiving surface: 1.0 cm ² , and the total thickness of the first layer and the second layer: 10 μm (thickness of the first layer: 3 μm, thickness of the second layer: 7 μm)), and then a photoelectrode 10 containing no sensitizing dye was produced.

Thereafter, an ethanol solution of the dye described in Table 9 (concentration of each sensitizing dye: 3 × 10 ^-4 mol/L) was prepared as a dye. Then, the photoelectrode 10 was immersed in the above solution and allowed to stand at a temperature of 80 ° C for 20 hours, whereby a total of sensitized dye was adsorbed in the inside of the semiconductor electrode to be about 1.0 × 10 ^-7 mol/cm ² .

Next, a counter electrode CE having the same shape and size as the above-described photoelectrode was fabricated. First, an isopropyl alcohol solution of chloroplatinic acid hexahydrate was dropped on a transparent conductive glass, dried in air, and then baked at 450 ° C for 30 minutes to obtain Platinum sintered to the pole CE. Further, a hole (1 mm in diameter) for injection of the electrolyte E is provided in advance in the counter electrode CE.

Next, a liquid electrolyte in which zinc iodide, iodized-1,2-dimethyl-3-propylimidazole, iodine, or 4-tert-butylacridine is dissolved by using methoxyacetonitrile as a solvent (iodination) Zinc concentration: 10 mmol/L, concentration of dimethylpropylimidazolium iodide: 0.6 mol/L, concentration of iodine: 0.05 mol/L, concentration of 4-t-butylacridine: 1 mol/L).

Then, a spacer S manufactured by DU PONT-MITSUI POLYCHEMICALS, which has a shape conforming to the size of the semiconductor electrode, is prepared (trade name: "Hi-milan", ethylene/methacrylic acid random copolymerization polyionic polymerization As shown in FIG. 1 of Japanese Laid-Open Patent Publication No. 2004-152613, the photoelectrode and the pair are disposed opposite each other by a spacer, and respectively heat-sealed to obtain a housing of the battery that is joined together (unfilled) Electrolyte).

Next, after injecting the liquid electrolyte into the casing from the hole of the counter electrode, the hole is plugged with a member of the same material as the spacer, and the member is thermally welded to seal the hole in the hole of the counter electrode to complete the photoelectrochemical cell 1 .

(Photoelectrochemical cell 2)

The photoelectrochemical cell 2 was produced in the same manner as in the photoelectrochemical cell 1 except that the concentration of zinc iodide in the liquid electrolyte was 50 mmol/L.

(Photoelectrochemical battery 3)

A comparative photoelectrochemical cell 3 was produced in the same manner as in the photoelectrochemical cell 1 except that lithium iodide was substituted for zinc iodide in the liquid electrolyte, and the concentration of lithium iodide in the liquid electrolyte was 20 mmol/L. .

(Comparative Photoelectrochemical Cell 4)

A comparative photoelectrochemical cell 4 was produced in the same manner as in the photoelectrochemical cell 1 except that lithium iodide was substituted for zinc iodide in the liquid electrolyte, and the concentration of lithium iodide in the liquid electrolyte was 100 mmol/L. .

(test and evaluation)

The conversion efficiency was measured for the samples used in the photoelectrochemical cells 1 to 4 in the following order.

The battery characteristic evaluation test was carried out using a solar simulator (manufactured by WACOM, trade name: "WXS-85H type"), and was irradiated with sunlight similar to sunlight from an AM filter (AM1.5). This was carried out under the measurement conditions of 100 mW/cm ² (so-called "1 Sun" irradiation conditions).

With respect to each photoelectrochemical cell, the current-voltage characteristics were measured at room temperature using an I-V test, and conversion efficiency was thereby determined. The results obtained above are shown in "initial value" of Table 9A (irradiation conditions of 1 Sun). Further, the results of the conversion efficiency after 300 hours of the conversion efficiency under the irradiation conditions of 10 ° under the irradiation of 60 ° C and 1 Sun are also shown in Table 9A. The initial value of the conversion efficiency is 2.4% or more, and less than 2.4% is unqualified. Further, with respect to the initial value, the rate of reduction in conversion efficiency after 300 hours passed was 20% or less, and more than 20% was unacceptable.

In addition, the evaluation was performed in the same manner as in the measurement of the conversion efficiency after 500 hours of the conversion efficiency. The above results are shown in Table 9B.

As is clear from Tables 9A and 9B, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency is an acceptable standard, and the reduction rate of the conversion efficiency after 300 hours has passed is 20% or less, and excellent durability is exhibited. .

Compared with the above, it is known that in the case of using a comparative pigment, the conversion efficiency The initial value is an acceptable standard, but there is a problem in durability.

[Experiment 10] 1. Preparation of titanium dioxide dispersion

Titanium dioxide fine particles (Degussa P-25, manufactured by Nippon Aerosil Co., Ltd.), 15 g of water, 45 g of water, dispersing agent (made by Aldrich Co., Ltd., Triron X-100) were placed in a 200 ml stainless steel container containing the inner surface of the fluororesin. 1 g of zirconia beads (manufactured by Nikkato Co., Ltd.) having a diameter of 0.5 mm and 30 g were subjected to dispersion treatment at 1,500 rpm for 2 hours using a sand mill (manufactured by Aimex Co., Ltd.). From the obtained dispersion, zirconia beads were filtered. The average particle diameter of the titanium dioxide fine particles in the obtained dispersion liquid was 2.5 μm. Among them, the particle size was measured by a Mastersizer (trade name) manufactured by MALVERN.

2. Preparation of titanium oxide fine particle layer (electrode A) for adsorbing pigment

Prepared a 20 mm × 20 mm conductive glass plate (manufactured by AGC Co., Ltd., TCO glass-U, surface resistance: about 30 Ω/m ² ) covered with fluorine-doped tin oxide, at both ends of the conductive layer side After the adhesive tape of the spacer was attached to the wide portion of the end portion of 3 mm, the dispersion was applied to the conductive layer using a glass rod. After the dispersion was applied, the adhesive tape was peeled off and air-dried at room temperature for one day. Next, the above-mentioned semiconductor-coated glass plate was placed in an electric furnace (muffle furnace FP-32 type manufactured by Yamato Scientific Co., Ltd.) and baked at 450 ° C for 30 minutes. The semiconductor-coated glass plate was taken out, cooled, and then immersed in an ethanol solution (concentration: 3 × 10 ^-4 mol/L) of the dye shown in Table 10 for 3 hours. The semiconductor-coated glass plate on which the dye was adsorbed was immersed in 4-tert-butyl acridine for 15 minutes, washed with ethanol, and naturally dried to obtain a titanium oxide fine particle layer (electrode A) which adsorbed the dye. The thickness of the dye-sensitized titanium oxide fine particle layer of the electrode A was 10 μm, and the amount of the titanium oxide fine particles applied was 20 g/m ² . Further, the amount of adsorption of the dye is in the range of 0.1 mmol/m ² to 10 mmol/m ² depending on the type of the dye.

3. Production of photoelectrochemical cell a

The solvent was a mixture of acetonitrile and 3-methyl-2-oxazolinone in a volume ratio of 90/10. To the above solvent, iodine and an iodide salt of 1-methyl-3-hexylimidazole as an electrolyte salt were added to prepare a solution containing 0.5 mol/L of an electrolyte and 0.05 mol/L of iodine. In the above solution, 10 parts by mass of the nitrogen-containing polymer compound (α) is added to 100 parts by mass of the solvent (nitrogen-containing polymer compound + salt). Further, the reactive nitrogen atom of the nitrogen-containing polymer compound was mixed with an electrophile (β) of 0.1 mole to obtain a uniform reaction solution.

On the other hand, a platinum film side including a counter electrode of a glass plate on which platinum is vapor-deposited by a spacer is provided on the dye-sensitized titanium oxide fine particle layer of the electrode A, and a conductive glass plate and a platinum vapor-deposited glass plate are fixed. The open end of the obtained assembly was immersed in the above electrolyte solution, and the reaction solution was impregnated into the dye-sensitized titanium oxide fine particle layer by capillary action.

Then, it was heated at 80 ° C for 30 minutes to carry out a crosslinking reaction. In the above manner, the conductive layer 12 of the conductive glass plate 10 shown in Fig. 2 of Japanese Laid-Open Patent Publication No. 2000-323190 includes the dye-sensitized titanium oxide fine particle layer 20, the electrolyte layer 30, and the platinum film. The photoelectrochemical cell a-1 (sample No. 10-1) of the present invention is sequentially laminated with the counter electrode 40 of the glass plate 41.

Further, in addition to changing the combination of the composition of the dye and the electrolyte composition shown in Table 10, the above-described process was repeated to obtain a photoelectrochemical cell a-2 having different photoreceptors and/or charge carriers (sample number 10) -4).

4. Production of photoelectrochemical cells b, c (1) Photoelectrochemical cell b

In the above manner, the electrode A (20 mm × 20 mm) including the titanium oxide fine particle layer sensitized with the dye of the present invention was superposed on the platinum-deposited glass plate of the same size by a spacer. Then, by capillary action, the electrolyte solution (the mixture of acetonitrile and 3-methyl-2-oxazolidone in a volume ratio of 90/10 as a solvent of iodine 0.05 mol/L, iodine) was used between the gaps of the two glass plates. A lithium metal 0.5 mol/L solution was impregnated to prepare a photoelectrochemical cell b-1. Further, the photoelectrochemical cell b-2 (sample No. 10-5) was obtained by repeating the above process except that the dye shown in Table 10 was changed.

(2) Photoelectrochemical cell c (electrolyte described in Japanese Patent Laid-Open Publication No. Hei 9-27352)

In the above manner, an electrolytic solution was applied to the electrode A (20 mm × 20 mm) including the titanium oxide fine particle layer sensitized with the dye of the present invention, and impregnated. Among them, the electrolytic solution contains 1 g of Hexaethylene glycol methacrylate ester (BLEMMER PE-350, manufactured by Nippon Oil Chemical Co., Ltd.), 1 g of ethylene glycol, and 2 as a polymerization initiator. Mixture of 20 mg of 2-hydroxy-2-methyl-1-phenylbutan-1-one (manufactured by Jiba-geigy Co., Ltd., DAROCUR 1173) In the solution, 500 mg of lithium iodide was dissolved and obtained by vacuum degassing for 10 minutes. Connect The porous titanium oxide layer impregnated with the mixed solution is subjected to a reduced pressure to remove bubbles in the porous titanium oxide layer to promote the impregnation of the monomer, and then to fill the micropores of the porous titanium oxide layer. A homogeneous sol of a polymer compound polymerized by irradiation with ultraviolet light. The article obtained in the above manner was exposed to an iodine atmosphere for 30 minutes to diffuse iodine into the polymer compound, and then the platinum vapor-deposited glass plate was laminated to obtain a photoelectrochemical cell c-1. Further, the photoelectrochemical cell c-2 (sample No. 10-6) was obtained by repeating the above process except that the dye shown in Table 10 was changed.

5. Determination of photoelectric conversion efficiency

The light of a 500 W xenon lamp (manufactured by Sushio Co., Ltd.) was passed through an AM 1.5 filter (manufactured by Oriel Co., Ltd.) and a sharp wave filter (Kenko L-42) to obtain a simulated sunlight containing no ultraviolet rays. The light intensity was 89 mW/cm ² .

An alligator clip is attached to each of the conductive glass plate 10 and the platinum vapor deposition glass plate 40 of the above photoelectrochemical cell, and each of the alligator clips is connected to a current-voltage measuring device (Keithley SMU238 type (trade name)). Here, the simulated sunlight is irradiated from the side of the conductive glass plate 10, and the generated electricity is measured by a current-voltage measuring device. The initial value of the conversion efficiency of the photoelectrochemical cell thus obtained and the rate of decrease of the conversion efficiency at the time of continuous irradiation for 300 hours are shown in Table 10. The initial value of the conversion efficiency is 2.7% or more, and less than 2.7% is unqualified. In addition, the reduction rate of conversion efficiency after 300 hours passed was 20% or less, and the case where more than 20% was unqualified.

(Remarks)

(1) The symbol of the pigment is as described herein.

(2) The nitrogen-containing polymer α and the electrophilic agent β are represented by the following compounds.

As is clear from Table 10, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency was an acceptable standard, and the reduction rate of the conversion efficiency after 300 hours passed was 15% or less, and excellent durability was exhibited.

In contrast to the above, when the comparative dye is used, the initial value of the conversion efficiency is an acceptable standard, but there is a problem in durability.

The present invention has been described above by way of example, and is not intended to limit the invention, and it is intended that the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

1‧‧‧Electrical support

2‧‧‧Photoreceptor layer

3‧‧‧Charge mobile body layer

4‧‧‧ pole

5‧‧‧Photoelectrode

6‧‧‧ Circuitry

10‧‧‧ photoelectric conversion components

21‧‧‧ pigment

22‧‧‧Semiconductor particles

100‧‧‧Photoelectrochemical battery

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view showing an example of a photoelectric conversion element according to the present invention.

1‧‧‧Electrical support

2‧‧‧Photoreceptor layer

3‧‧‧Charge mobile body layer

4‧‧‧ pole

5‧‧‧Photoelectrode

6‧‧‧ Circuitry

10‧‧‧ photoelectric conversion components

21‧‧‧ pigment

22‧‧‧Semiconductor particles

100‧‧‧Photoelectrochemical battery

Claims (5)

A photoelectric conversion element comprising a photoreceptor layer having a pigment and a semiconductor fine particle, wherein the dye is a compound represented by S-14, S-15 or S-16. The compound represented by S-14 is represented by the above formula wherein X is C(CH ₃ ) ₂ , Y is C(CH ₃ ) ₂ , Z ¹ is C ₁₀ H ₂₁ , Z ² is CH ₃ , and R is C ₁₀ H ₂₁ . V ² is a compound in which 4,5-benzene ring is condensed and V ³ is 5-COOH; the compound represented by S-15 is in the above formula wherein X is C(CH ₃ ) ₂ and Y is C(CH ₃ ) ₂ , Z ¹ is a compound in which C ₁₀ H ₂₁ , Z ² is C ₈ H ₁₇ , R is C ₁₀ H ₂₁ , V ² is 4,5-benzene ring condensation, and V ³ is 5-COOH; the compound represented by S-16 is In the above formula, X is C(C ₅ H ₁₁ ) ₂ , Y is C(C ₅ H ₁₁ ) ₂ , Z ¹ is C ₁₀ H ₂₁ , Z ² is C ₁₀ H ₂₁ , and R is C ₁₀ H ₂₁ , V ² It is a compound in which a 4,5-benzene ring is condensed and V ³ is 5-COOH. The photoelectric conversion element according to claim 1, wherein the semiconductor fine particles are titanium oxide fine particles. A photoelectrochemical cell comprising the photoelectric conversion element according to claim 1 or 2. A pigment for a photoelectric conversion element, which is a compound represented by S-14, S-15 or S-16, The compound represented by S-14 is represented by the above formula wherein X is C(CH ₃ ) ₂ , Y is C(CH ₃ ) ₂ , Z ¹ is C ₁₀ H ₂₁ , Z ² is CH ₃ , and R is C ₁₀ H ₂₁ . V ² is a compound in which 4,5-benzene ring is condensed and V ³ is 5-COOH; the compound represented by S-15 is in the above formula wherein X is C(CH ₃ ) ₂ and Y is C(CH ₃ ) ₂ , Z ¹ is a compound in which C ₁₀ H ₂₁ , Z ² is C ₈ H ₁₇ , R is C ₁₀ H ₂₁ , V ² is 4,5-benzene ring condensation, and V ³ is 5-COOH; the compound represented by S-16 is In the above formula, X is C(C ₅ H ₁₁ ) ₂ , Y is C(C ₅ H ₁₁ ) ₂ , Z ¹ is C ₁₀ H ₂₁ , Z ² is C ₁₀ H ₂₁ , and R is C ₁₀ H ₂₁ , V ² It is a compound in which a 4,5-benzene ring is condensed and V ³ is 5-COOH. A dye solution for a photoelectric conversion element containing, in an organic solvent, a dye for a photoelectric conversion element according to item 4 of the patent application.